Easy win:
Choose a side to play on. Then, during gameplay, press Start and choose "Select 
Sides". Move your controller under the opponent's side and resume gameplay. 
Then, score as many goals as desired (while under the opponent's side), then just 
switch back to your side again. This way you will have a big point lead, depending 
on how many goals you scored. This trick also works better when you switch back 
to your side near the end of the second half.

Getting good players:
Go to the options menu then to "Player Swaps". Swap all the good players desired 
onto the team you want to play as, then save that as a squad. Call it whatever 
desired. Then go to "New Season" and select "Current Squads" and play your 
team. This is useful for a third division team. This team now has all the good 
players.

Buying players:
If you want to buy a player, bid for them about 1 or 2 million above the asking 
price. This ensures you of signing that player. Players that are worth buying 
include:

Thierry Henry
Ronaldinho 
David Beckham
Ronaldo (either)
Tim Howard
Roberto Carlos
Alexandre Del Piero 
David Bellion
Ruud Van Nistelrooy
Hernan Crespo 

In the first year, it is almost impossible (unless you bid over 5 million above the 
asking price) to buy Thiery Henry, David Becham, Ronaldo, and Del Piero.

Recommended team:
Create a team with the following players.

Goalkeepers
Tim Howard
Iker Casillas 
Defenders
Rio Ferdinand
Paulo Maldini
Alexandre Nesta
Roberto Carlos
Lilian Thuram
Sol Campbell 
Midfielders
David Beckham
Zinedine Zidane
Cristiano Ronaldo
Luis Figo
Ronaldinho
Edgar Davids
David Bellion 
Forwards
Thierry Henry 
Ruud Van Nistelrooy
Ronaldo
Del Piero
Shevshenko
Adrian Mutu
Hernan Crespo
 
Create a team with the following players. Note: The players are expensive so you 
might have to sell some of your best players first. The subs are up to you.

Defenders
RB: Michel Salgado (Real Madrid)
LCB: Fabio Cannavaro (Inter Milan)
RCB: Alessandro Nesta (AC Milan)
LB: Roberto Carlos (Real Madrid) 
Midfielders
LM: Zinedine Zidane (Real Madrid)
RM: David Beckham (Real Madrid)
CAM: Ronaldiniho (Barcelona) 
Strikers
LF: Ronaldo (Real Madrid)
RF: Theirry Henry (Arsenal)