I keep seeing this game appear and it looks like it's perfectly up my alley, but I've tried it several times and I just cannot find out how to advance. It just seems to take an eternity of grind to get anywhere... if other people have a different impression, can you please share with me some tips for getting anywhere in a timely fashion?
PQ isn't designed to give lewds/sex right away. Treat it as a regular rpg that happens to have LOTS of sex once you hit milestones.
PQ quest progression is pretty linear at the beginning, it's the oldest part of the game and Tinkerer was learning how to build it. It gets more flexible as you advance. Many girls' questlines can be ignored if you don't care for their stories, though virtually all of them provide in-game benefits in addition to sex if you pursue them.
You do need a chunk of money to gear up so some early grinding is probably a necessary evil if you don't use the Cheatmode mentioned by
DomWolf. The need for cash grinds doesn't totally go away for a while, but does drop significantly once you hit (IMO) level 7-8. And there are quests which give passive income on completion (the cash automatically accrues periodically).
Save regularly, especially before fighting tough opponents. Turn on Autosave immediately at game start...at worst you can start over at the beginning of that day if you die/fuck something up. A useful technique is scumsaving (Save right before something and reload if you die or don't like the outcome), especially for grinds. You don't have to Save before EVERY fight/event, but too many people don't seem to Save at all.