1) Quality of life. This relates to the "luxury" stat. The higher the grade of a girl (slave - poor - commoner - rich - noble), the more "luxury" they demand. You can increase a girl's luxury in a few ways. Private room or your bed (some mansion upgrades make this give even more luxury), underwear/boxers, or the gold ring from the beasty northerners.
2) Fairy quest - definitely the biggest jump I think - second quest and you're fighting really high level guys. I find the wolves to be the easiest grind - they die pretty easily so you can get a few good fights in before having to rest. Find them around Amberguard - one jump north from Wimborn Outskirts in the Forest has a bunch. Having 4 in your group also is a huge jump over 2 or 3 - taking the girls from Wimborn, buying (or capturing) a few good fighters will make a huge difference. I'd focus on getting a group of 4 at level 2 or 3, then go up and try to get a fairy. I find they either spawn as level 3 or 6. For this quest just capture a crappy level 3. Then go back and capture a level 6 because they have high magic and can become a good mage in your group, and reasonable to defeat with 4 level 2/3s because they're always alone.