1 - when you still have about 2-3 full strides (assuming you are moving) before reaching the defender. these do not automatically equal success in faking out the defender though. you are hoping for them to stop/slow their movement, or bite on a fake so you can go the other way. if they continue to barrell into you (85%+ of the time), your skill move was for nothing. yay FIFA cpu AI
2 - crossing is a tougher to gauge. if your player is running hard down the wing, send the cross when you are still a step or two away from where the edge of the box would extend towards the sidelines...momentum will have the ball swing dang near the middle of the box the majority of the time. or you could be 5-6 strides outside the box, use the L1 modifier to "early cross" so your guys can run onto it. if you have space from the defender, come to a near stop about 2-3 strides in from the box and just fire it straight in. the aerial game is a WHOLE other story, but you will at least have the crosses in there more!
3 - unfortunately, your guess is as good as anyone's...seems VERY difficult (dare I say random?) so have success in the air with any regularity in 10
4 - depends on the strength of the tackle. if you have had seveal running steps into the tackle = more likely for a foul. my advice, use the jockey instead to keep in front and then use tackle (when you are already within a step or two of the attacker) when he pushes the ball a bit too far away.
5 - if you are using a guy with some speed DON'T SPRINT (just jog) until the defender comes within a step of you, then blow past him. I'd guess at least 75% of the time you will get the step on him. if it looks like he is going to tackle you, flick the RS to knock the ball past him, sprint on by, enjoy your breakaway!
6 - not exactly sure what you mean. the closer you are to a defender, the harder it is to pull off, but the more likely you are to get around him.
7 - check out all the threads on this. on all manual it is much easier to hit the target when you position your body as opposed to "aiming"...it is not easy and very frustrating. unfortunately, just stick with it, and it really does get easier with time. I, myself, cannot nail the corners at will, but I find that I can at least get 6 or 7 quality chances (nearly 10 shots) per match (6 mins)
x - frustrating as all hell. I think the guys are just plain dumb more often than not. I have not found any rhyme or reason for the guy to run on or not move