Start as five star team in Career mode
Unlock career teams in the My Fifa menu. You can do this by completing the challenges set.
Full stat team
To start with a five star team immediately in Career mode, go to the team management screen. Put the bad players in the first eleven so that your team will be a four star team. Then, go to Career mode and your team should be there. Save your career, then go back to the team management screen.
Put the first eleven players back, save it, and you will have the normal team on friendlies and your team on Career mode. Additionally, you can make any team have full stats by editing each players stats and upgrading them to 99. However, if you start with that team in Manager mode, your salary will be high. Make sure to cut their contracts down as soon as possible.
Use the following trick to be any team desired in Career mode without buying better career teams from the Fan shop. Go to team management and select a four and a half or five star team. Put all their worst players into the starting line up. They need to be at about four stars or below, then you can then use them in Career mode. When you have begun your career you can change your team back.
Fully fit team in Manager mode
In Manager mode, notice that the energy bars of your players decrease after each match. Save your career, then go back to the main menu. Load your career again. Your team will have full energy again. Note: This may not work the first time. Save and reload the game maybe once or twice more for it to work.
Win everything in Manager mode with any team
Pick a team, then start your career. Save your game. Choose "Next Match", then "Quick Sim". If you win the match, save your progress. If you lose a match, return to the main menu and load your career again. You can have as many chances as you want against a team, as the outcome is random every time. Make sure to save your progress after every win, in case you lose unexpectedly.
Increase profits in Manager mode
At the start of your season, do not spend the money you have immediately on staff upgrades and new players. Instead, spend the money you have on renewing player contracts. Wait to get your players morale up first, as they will be more likely to accept a renewal if they are happy at the club. You can sometimes cut a player's salary in half, if not more. Make sure to save the game before renewing contracts so that you can start low, and increase each time if the player refuses the renewal. If a player refuses the renewal at a high price, and they have a high moral, then it may be because they are close to retirement. This can earn you up to 3,000 credits (off your current salary) each match if done well. Including a good sponsor, you could be earning 7,000 to 8,000 credits each game when at home.