One of the main parts of my approach is that I rarely use the transfer market, although I have been dipping in a bit more frequently lately. Also, not using the TL and having a big arena leads to a good amount of $$$ in my bank account.
Not for everyone and probably useful only in small countries, this is how I have played-
** very early on ( after making a few major beginner's blunders ) sold my best player to get solvent. have continued the tradition by TL-ing one of my best players early on in each season. This allows for younger players to get more minutes and provides me with operating capital.
** trained all positions on a rotating schedule
** increased my stadium as often as possible instead of buying and selling players
** bought decent old players very cheap to fill weak positions
** read the rules and forums extensively.
** always kept my roster to 12 players so that all of them get 48+ minutes every week leaving me with lots of training options.
Once I scored a basket that still makes me laugh.