So as most of us know, there are a few methods for boosting. Whether it be in Rumble Pit or Invasion, or using the Target Locator in ONI: Sword Base or Gruntpocalypse. I'll update this thread if it stays alive and if I find more methods as to ranking up.

IMPORTANT!
Thanks to -Justin, this should clear up a few questions.

"Will I be banned for playing <my favorite gametype>?
Nope. You wont be banned for legitimately playing Reach. If you find some particularly fast way of earning Credits because you want to be the first person on the planet with thunder and lightning swirling your visage, we wont ban you for that, either. Assuming youre actually playing, your efficient means of farming Credits will only expedite your trip to the Daily Cap it wont send you to Banadu." From Bungie's Weekly Update. Now stop asking if you'll be banned.

ALSO IMPORTANT:
Read the first post of this.


UPDATES:
9/24/10: Added FAQ section, and ratings to the commendations earned. (Scale of 1-10)
9/26/10: Added 'Challenge Reset', and added more FAQs.
9/27/10: Updated 'Challenge Reset', added more FAQs.
9/28/10: General updating.
9/30/10: Added 'MAC Cannon Holdout', added more FAQs.
10/1/10: My cR was reset, and I was banned from Matchmaking, along with many others.
10/3/10: Edited the 'Challenge Reset' section, added more FAQs.
10/10/10: Stopping in to add a few things, and say that I lost the game.


Target Locator:

To do this, you need to go into Campaign and select ONI: Sword Base on Heroic with Team Scoring on Free For All, with the Cowbell skull on (Thunderstorm is optional, for getting SpecOps and Leader Element). When the mission starts, run directly to the right and go up the ramp and don't kill anything. Hang to the right as you run to the garage and when you finally get to the bunker with the Target Locator, pick it up and run to the part of the door that's closed to try and get a checkpoint. If and ONLY when you get a checkpoint, shoot the target locator into the group of enemies and watch the multikills stack up. Commendations you can get from this: (In order from most points to the commendation)

- Splash Damage (10)
- Walking Tank (9)
- SpecOps (5)
- Leadership Element (5)
- Super Soldier (5)
- Cannon Fodder (6)

The above method is the fastest way to earn credits as via boosting. But eventually, about the time you earn Onyx for Splash Damage, the credits go up much slower. So this becomes ineffective over time.

Gruntpocalypse:

This is the most widely known and used method, basically, you go into Matchmaking and hit up Score Attack. When you're in the lobby, keep voting for 'None of the above' until you get Gruntpocalypse on Corvette. Corvette is the main map for doing this due to its small size and the Grunts spawn in clusters and the multikills are good. Go for headshots, and watch your back. Commendations you can earn, in order from largest points:

- Dome Inspector (10)
- Numbers Game (7)
- Target Practice (8)
- Longshot (7)
- Methodical (3)
- Specialized (5)
- Pull the Pin (1)
- Trigger Happy (5)
- In Command (3)*
- Perfectionist (5)

The above method is very useful for getting points, I finish each game in 6 minutes or under and I get a good 1,200+ points every time.

Repetitive Legendary Win (Thank you, TehBanStick)

This was originally posted by TehBanStick, his post his below so if this helps, scroll down and +Rep him, because he posted this.

Basically, you go through any campaign level on Legendary (preferably Winter Contingency) and when you get to the end (where you kill the 2 Zealots and reset the junction) as soon as the screen goes black, wait about 3 seconds and press start and hit 'Save and Quit'. If you did it right, you should Resume Campaign and it should start you at the cutscene and you get <200 cR about every 10-15 seconds. You MUST have free-for-all scoring on and it MUST be solo. Commendations earned:

- Demon (10)
- Flawless Cowboy (10)
* Bragging rights, for having Onyx in the two named above.

Get Loud!

My friend XxI EpiK IxX told me how to do this, so props go to him, he doesn't have a 7S account but if you appreciate this method, send him a message over XBL.

Similar to the Gruntpocalypse method, you're going to choose Crashsite instead of Gruntpocalypse. The map is inert. Now since in Crashsite you have infinite ammo, weapons that are scarce with ammo are now more useful. Such as a Rocket Launcher or a Fuel Rod Cannon. What you want to do, is find a Grunt specialist with a Fuel Rod Cannon and kill it as soon as possible. Pick his Fuel Rod Cannon up and rush to the generator and protect the generator while using the Fuel Rod to quickly dispatch groups of enemies. Use this when the enemies first spawn and you will get large amounts of multikills. Commendations earned:

- Get Loud (8)
- Numbers Game (10)
- Target Practice (6)
- Methodical (2)
- Specialist (5)
- In Command (3)

MAC Cannon Holdout

Okay, a little work to do from the beginning, but start 'The Pillar of Autumn' on Normal, what you want to do is go through the mission until you get to the part where

Emile dies
and you're at the MAC Cannon, don't get in it. Make sure you get a checkpoint either when you're right beside the cannon or inside of it. Once you get a checkpoint, shoot everything in sight and when Captain Keyes tells you to shoot the Corvette, don't do it. Revert to last save or let it glass everything, whichever you choose to do. Just keep shooting everything down and reverting, great for vehicle kills. Commendations:

- Right of Way (9)
- War Machine (?)
- Super Soldier (2)

War Machine:
Pretty sure a few people posted this here, props to you guys.

On Tip of the Spear, any difficulty, play through it until you get to the Falcon. It should have grenade launchers on the side, and you should also get a checkpoint before or after you enter it. Go through it until you kill all the enemies and revert. Simple, right? Commendations:

- War Machine (8)
- Right of Way (3)

Vehicular:
Contributed by Mr Famous on the 9th page.

Run Score Attack and choose Score Attack on Beachhead. Grab the Warthog and drive it on top of a hill where you will not get hit by any projectiles (grenades, fuel rods, etc.) and get in the turret and basically turret-snipe everything in sight. Commendations:

- Vehicular (10) (Proper name of Commendation? Correct me if wrong.)
- Numbers Game (5)
- Target Practice (7)
- Specialized (7)
- And others...

Challenge Reset:

This is the boosting method some people fear, due to the fact that you may get banned.

This is also a glitch that some people stretch into their own ways to fit personal preferences, as I have done. If you don't like my way, improvise.

Okay, what you're going to do, is when there's a daily challenge for getting kills in Firefight, such as today's (10/24/2010) One Spartan Army. Go into Score Attack and hit 3 Gruntpocalypse games and kill all of the grunts. You should have around 358 total grunts killed when you're done this. Now go into a 4th and final Gruntpocalypse game and use a little bit of simple subtraction and find out exactly how much more grunts you need to kill. Once you hit 399, leave the game. Now go back into the lobby and do Crashsite instead. When the Phantom drops off a grunt, kill it and immediately pull your ethernet cord. Let the enemies blow up the generator and when you're in the lobby, connect back to Xbox LIVE and repeat the steps starting from when you enter a Crashsite game.

Also due to the fact that daily challenges change... Well, daily, there are many possibilities to do the challenge reset glitch in many different instances. Challenges you can do in Campaign are the BEST and there is a significantly lower chance of being cR /matchmaking banned. However, there are always risks. I was banned the day they put out the new automatic banning system, even though my rank was about 95% legit. I don't agree with how they did things but it happened and I'm not going to beg every staff on b.net to restore my rank.

Commendations:

- None, really.
- MASSIVE cR gain, though.

Now, these are all we know so far, if you've got ANYTHING, post your ideas here, we can improve them, improvise, and most importantly, rank up. We all want that, don't we?

FAQs: (Frequently Asked Questions)

Q. For the 'Repetitive Legendary Win' trick, does it have to be Legendary?
A. Well, no. The Flawless Cowboy counts if you beat a level without dying on Heroic or Legendary. But if you want Carter's avatar helmet, do it on Legendary. I died about 2 times on Winter Contingency, it's not hard.

Q. Can I die while doing the RLW trick?
A. Yes, resuming solo campaign clears your death slate.

Q. Why does my cR accumulation go down the more I do one of these tricks?
A. Quite simple, as your commendations go up, the cR earned goes down. I don't quite have an explanation as to why it does this, it's more logical to reward players (or cheaters like us =P) as they get a higher commendation level.

Q. Will I get banned?
A. Technically, you are exploiting a glitch and/or method in a game to rank yourself up faster which does indeed break some kind of Xbox Live Term and Policy and whatnot, but the odds of you getting banned are thin. Things that will get you banned are;

- Resetting your challenges (More likely to get banned in matchmaking.)
- Basically anything having to do with resetting a cap, challenge, or exploiting a glitch by disconnecting your ethernet cable, etc.

Q. Can you get banned for resetting daily challenges?
A. Yes, but as the automatic banning system is still underway, you may be able to work your way around the ban with a simple PM to a moderator on this site. Any excuse along the lines of "I was randomly disconnected during a game and the challenge reset by accident," should do. Another tip, don't rank up too much in one day. It IS possible for a normal person to go from Captain to Major in a day by playing well in Matchmaking, so try not to go crazy with ranking up.

Q. Can I reset any challenge?
A. Of course, the one I used in my explanation is just an example, and you can substitute it out for any other challenge.

Q. My cR isn't going up, what do I do?
A. A lot of people have this problem, it means you have been credit locked. Not a bad thing necessarily, it just means you've hit your cap. There's a way to get past it, and that's by changing your time zone to +14 Kiribati and going into an online game and your credits should be unlocked. However, going past the credit cap means that you will be locked for an extra 24 hours.

Q. People tell me that resetting your challenges in Campaign will not get me banned as opposed to resetting them in Matchmaking. Is this true?
A. It's bullocks. Meaning, no it is not true. This is network manipulation, and it was known from the start by people who reset challenges that they were likely to get banned. However, I did reset my challenges in matchmaking and I was banned. But my friend who did it in Campaign was also banned, so whoever told you this is on crazy s***.

Special Thanks:
ME <3
-Justin