I've found if you were good on FIFA 15, most people will probably find FIFA 16 difficult unless you adapt to the new mechanics and controls of the game, i have a few tips that may help.

R1+X is really important this year for a more precise speedier pass, for example if you are playing from defense and want to get the ball to the wings or to a central player you have to use R1+X, using just X will get the ball intercepted 90% of the time and should only be used for short passes. Passing really irritated me at first and i still havent completely nailed it, but if you keep trying them and working out where they work and where they don't you will get used to it.

Finesse shots are alot more effective in the box now, you can beat the keeper near post alot more this year. Also double-tapping circle in the box gives you a ground shot which is great.

The power bar is different this year i've found you need to put slightly more power on your shots and passes, when i first got the game my shots were so tame but i realized the power bar builds up slower than last years, so don't be afraid to use more power when shooting, especially outside the box.

Off the ball dribbling is actually pretty effective, usually i'd pass it off as gimmicky and something i'd rarely use but it's handy getting around a player especially on the wing. Using L1+R2 and pusing the left stick in whichever direction, makes your player do a large feint then you can pass around a player if you time it right.

Holding R1 while sprinting makes your player alot more agile and allows you to manoeuvre around players easier, i've found tapping R1 as you get to defender your player will do a small tap on and helps you change direction quicker.

Putting backspin on your shots around the box is really fun this year, for example using a powerhouse like Toure will create a really powerful dipping shot. As soon as you receive the ball just outside the box do this straight away and it will get you a goal most of the time if done right.

For defending i tend to hold L2 and x when 1 on 1 (this tends to keep you locked on to the player in front of you and makes it harder for them to get past you) and then choose the best time to make the standing tackle, . Sliding tackles is pretty much the same as last year and i try not to use them too much, because if you get them wrong it causes mayhem and will probably lead to a chance on goal.
Remember to not rush your midfield into tackles just pull them back nearer the defense and wait for the opposition to make an error or until your able to put a tackle in.

Most will probably know this already but Holding L2 and R2 is really effective at sealing a player out especially in midfield when you have your back to the opposition then you can make the pass back to defense or the wings.

Hope this helps some people because i really didn't like the game at first so i forced myself to work out what buttons combinations i need to be using this year and it has helped me a lot, i find myself winning a ton more games now when i was losing 8/10 games at first. Let me know if something doesn't make sense, it's my first time writing up something like this. I will add to this if i think of anything else.