For me, there is no need to cheat at all.
First couple round, just catch some girls and brothel once, then sell to unlock rooms. Meanwhile emember to collect green lighten Fairies. One girl can sell for 1K to 2K in total, and train some All 0 girls for combat.
After collect 5 fairies, you can spend them at well, and enter a Dungeon which every stages have Witches' Arena, there are always 7-9 girls in there. Found some weapon like multi-fireballs will allow you smash them without difficult.
Catch & sell, after you unlocked Prison, you can catch a lot girls in a row (every stages need one lover to clear through). Selling those not your types in prison will give you so much money that don't know how to spend.
