im currently managing everton and i have spent about 50 million over the past 4 season yet i got them to 2nd last season, 4th the season before and 3rd in my first season as well as winning the UEFA Cup. This season, my fourth with Everton I am currently 1st in Novemeber 3 points clear of Man City.
How did I do this? I kept the squad pretty much the same I only sold off dead wood but kept my base first 11 the same as much as possible only signing 2 or 3 players each window apart from my strengthening of the youth team now my first 11 is:
GK: Tim Howard
LB: Leighton Baines
CB: Jack Rodwell
CB: Brede Hangeland
RB: Jack Cork
LW: Dinijar Bilyaletdinov
CM: Tim Cahill
CM: Nenad Milijas
RW: Dudu
ST: Victor Anichebe
ST: Jose Baxter
Out of those 11 players only 3 of them were signed in 4 years (Dudu, Milijas, Cork) all the rest have played in the same team for 4 years and I have an established tactic which is why I could beat Man United 4-1 despite the fact they have spent probably about 5 times more than me.
The moral of the story do not sell or buy unless you have to! Only sell a player if you
1) Need to trim the wage budget
2) You have excess players better than him for his position
3) He is unhappy
4) He is an average player in bad form
Do NOT sell a key player or first team player who is in bad form! In my first season Anichebe scored 6 goals in 15 games which was pretty good, next season he took a turn for the worst and scored 5 goals in 22 games going on a really bad drought towards the end of the season that saw him go something like 600 minutes without scoring, I considered selling him and splashing the cash on a proven goalscorer but kept him and the next season he scored 17 in 21 in the league and 7 in 5 in the cup.
This season he's scored 5 in 9 league games.