What skills would that be? Decorations? They seem to be random. Lvl for prestige or if you have a good one, lvl that higher.
Oh the skill skills. Depends. How fast and how much do you click? Offline increase of income is good. But if you have the game open that will not help. If you click a lot, the skill that collects all girls with private show on is good.
All the gem spending options suck.
Save your keys for later. Open lvl 10 chests. More items. More chance for time skips.