Strat goes like this:
Sell 3* fast trainer for 750K, buy same free agent instead of him. Use extra cash and buy young 5* (20-25Q) player or few older.
At the end of season sell 4* (15-19.9Q) rating FA that used to have 3* (U15Q). Next season buy free agents 3* (15-20Q) rating.
Spend extra cash on new 5* players (25-29.9Q)