I pulled a couple off in the demo. The key is to not over do them (don't try to do a flip flap with Cannavaro). You know who to use especially if you use the same team alot. For example, on Real, I know I can pull moves off w/ Robinho, Robben, and simple ones with Raul. Timing, player, defender, angle, fatigue, etc is everything. It takes practice. Just don't try to pull them all the time.
i sort of guessed all that, i just cant get them to work properly, all im good at is the one where you push the right stick up down up and he back heels it onto the other foot and then it goes forward again but that doesnt do anything to beat a player, do the step overs and body feints actually trick the computer?
To be honest, skill moves works better on third person view (Be a Pro), on a normal macth i dont use too much the tricks thing, i preferd to use stop and go, right stick first touches, or mantain positions with LT, search for a through pass, etc...May be to use the tricks on a determinate moment its ok, for example, on the wing, a flip flap, or fake shoot, etc...but dont try to abuse too much of this movements. As Orgullo says, it´s better to do the skills moves with players that you assume that they can do it in real life, Messi, Ronnie, Raul, Torres, Gerrard, Henry, etc... Anyway is a thing of practice, of course.