It is very different to COD, not saying that being a COD player won't help it, but you will need to learn how to control your recoil, accuracy when shooting and getting used to the maps, guns, and the concept of skins.

The biggest advice I could give you if you are coming from call of duty would be that CS GO is a team game so don't rage at your team when they do something wrong also don't rush when your CT and learn the call outs since communication is key in a game like CS GO.

If you need any tips you can always check out my mega thread here as I have some useful information to help new players.

A few tips would be to download some aim training, spray control workshop maps, practice on community servers and find someone that is experienced at the game and ask them to help you.
I can help you if you want, if so PM me and I'll get back to you.

Learn call outs, dont assume AK is easy to use either people make that mistake its very hard to get used to, find a gun you feel comfortble using and learn the spray pattern and recoil control

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This just about sums it up

Play deathmatch it will improve your accuracy and try not to spray especially with guns like AK.

Practice makes perfect, i death match for like 3 hours a day, and im still only gold nova 4.