Tactics - one tactic I always used no matter what its free form attacking instead of organized. I hate how if you take your striker to the left wing, the LW will just trail him, so instead in free form, he will attack the middle where your striker just was.
Tips - do not just buy high rated players because there rating is high, take a look at things that you need in your play style, ex. high stamina if you sprint alot, or skill moves if you do tricks. I personally will always stay away from players with stamina under 70.