This might be classed as tipping, in which case I apologise to everyone sincerely
I have found that a few home friendlies at the start of each season as a conference or conference north/south manager playing against (if you're lucky) a premiership club, or one of the bigger championship teams can work wonders for your bank balance.
I have been playing as Runcorn FC Halton in the Conference North. They ground share in real life with Widnes Vikings Rugby League team at a 12,000 all seater stadium, which is true in-game also. (Although in real life they have been booted out of their ground for not paying the rent & are on the verge of going to the wall!!)
Surviving on paltry average crowds of 200-300 max can be pretty hard going, but I played friendlies against Nottm Forest, Preston, Derby, Coventry and Leicester and got near capacity crowds and about £60k per game!!
The fun part about being a LLM is that for my first league game agains Ashton United, all 221 of my clubs loyal supporters turned up!