Step one, scout your division, look at there arena's (size and prices and look how filled they are)
Step two look at your cash and start building the seats you need. Start with easy fillers. Bleachers and no lux boxes
Step three, look at your place in rankking, and make the prices acording to your place in te ranking.
It has no use building seats foor 29k, just wait until you have some more and build voor 100 or 200k
Then change the prices at the beginning of the new season, when you win a lot of games and it is sold out (90%) then invest in more seats and raise the prices SLOW so dont go from 10 to 20