One mistake i see a lot of people make on defense is there natural reaction to instanly move foward with their defenders as soon as they switch to them. What i do is make sure i run back a little or stand my ground then hold LT and just follow where the guy on the ball is and cut off his angle to goal and try to push him out to the corners. Then if he tries to cross it hold down X in the direction the service came in from it is a very effective way of clearing headers.

Don't slide, i rarely slide on fifa, just stand them up. I hold rb and with another player just watch where he can pass, if you think a one-two is going to happen just hold Y and for me my keeper does a lot of defending.

Keeping the ball is quite hard on this fifa especially when your always tempted to Lb and Y it over the top, just do short passes and wait for it to open up then shoot.