Always check the player status
screen before you sell a player. If a player has a
close friend on the team, this will cost a lot of
morale. This could be disastrous if the remaining
player is one of your stars.
Easy money
Go into Club/Stadium
Facilities/Stadium Expansion. Change the stadium type
(rounded corners, oval; this will cost you money) and
select "Build Stadium". Do this again (changing the
stadium type, build it), and you will receive money.
Note: Do not do this if you are thinking about
building a new stadium.