Playing FIFA 10 which is a very passing oriented game, you need to have some sort of plan or tactic if you expect to do well. This tutorial features a number of game tactics or points of focus which you should keep in mind when you're playing competetive matches. Many of the best FIFA players will agree that it is very beneficial to have a structured way of playing as opposed to "just playing". Read more here.
The D-Pad offers a method of having the computer structure your team for you. This can be incredibly useful, although many ignore this. Setting your team up for the Posession Game when you need to run the clock out can make that small difference needed between you and your opponent. Read more here.
A feature that debuted in FIFA 09 was the ability to set your own Custom Tactics, and this feature returns in FIFA 10. These Custom Tactics are basically your teams "settings", so to speak. You can specify how quickly or intensely you want your team to defend, attack, posess, pressure, etc. to your liking. Remember that every tactic that is increased, there is a drawback of some sort, so find that perfect balance. Read more here.