It seems the guy above has everything you really needed so I only tell my best tips to win.
+There is no such thing as best formation for the team. Each formation and tactic counter each others in different ways. So you should have 1 offensive, 1 basic ( the main formation you use ) and 1 defensive-counter formation (only use in desperate match when you have very low chance of winning and seeking a draw )
+ The same formation can vary hugely if you assign different role for your players. For ex: A deep lying play maker and an advanced play maker are 2 different entities, a winger and a wide middle fielder can bring a huge different in tactic, so do a defensive middle fielder and an anchor man. So my suggestion is: For the same position you should have players suitable for different roles, it will increase your options and make your tactic more flexible. My key to success with the most basic formation 4-4-2 (in my opinion, it's the most complete and balance formation in football ) is very simple with 3 type of rotations
+ Mid field rotation between my advanced, deep lying play maker and my central, ball wining middle fielder. For ex: Against strong teams play super offensive 4-2-3-1 I use 1 ball wining and 1 deep lying, set tactic to exploit the flank and have my wingers as main attacking outlet. Against super defensive teams I use a central mid and an advanced play maker. Normally I use a ball wining and an advanced.
+ Wing rotation: I normally use 1 support and 1 attack winger, but I also have 2 wide middle fielders with very high work rate, their sole purpose is for the mid field battle against team who pack their mid field with 5 players or more. I also use my wide middle fielders when the opponent play mainly through the center (so that they can fight for the ball and cover for my wingbacks who will constantly overlap for crossing ).
+ Forward rotation: One of the most important: I have 3 favorite combination in this one: deep lying/ advanced forward ( for normally use ). Targetman/ poacher (For counter attacking oriented matches, work well with a deep lying playmaker ). Complete forward attack/support (for heavily defensive teams ).
It's fairly simple yet very effective, the flexibility comes from the simplicity, at least for my no fancy 4-4-2 tactic it works well in long term (at least against the computer ). If you are not a complex thinker or a master mind tactician, you should give a try. Please note that it's possible to use one player for different roles so you may not need to turn your team into an army.
+ Another tip is instead of trying to make an all star team, you should invest more in some roles and less in others. Choosing and using your key players wisely and let your whole team rotate around them. I usually have 4 key players: The fast striker/main goal scorer (who can be good advanced forward, poacher, it's hard to get a good complete forward ), The deep lying play maker (most deep lying can also play central mid if needed ). The central defender (Usually do cover duty for the *** saving situation ) and the goal keeper (a good goalkeeper is a must if you want to success ).
There are few thousands other tips but these are my most simple and useful. Good luck then.
