Make as much custom players as you can and make put there stats all to 99, send them to your team you want to start you career with and you can either sell them for around 12.000 each or keep them, if you keep them you can easily get promoted by quick simulating every game.
You'll get points when you beat something. With these points, you can buy several things in the Fifa Shop.
A list of from what you get the points, in order of the amount of points you get, from high to low.
FA Premier League: 1500
English Cup: 1000
Beat the 5-Minutes Challenge: 750
Win the 'Underdog' Challenge: 500
First and Second League: 500
Hattrick Challenge: 500
Scottish Cup: 500
Vans Trophy: 500
if you get a direct free kick near the center of the pitch, aim as low as possible, don't put any spin on the ball and hit it as hard as possible, it will hit the cross bar nearly all the time.
Not so much a cheat as a tip, but if your weekly salary expense is over-riding the sponsor payments simply do the following and it should be of some use:
Go to Team Management in Manager Mode, and select "Player Contracts".
Find a player with 2+ years left on his contract and with good morale then select him and lower his salary by 40-60 points.
Repeat with as many players as you can, if 10+ accept your offer then that's 400-600 saved on salary without any damage done.
Don't worry if they decline your offer, you'll still have 2 seasons to renew the contract anyway.