I generally make my MC as a fighter, so I can max charm and maybe sex, then put 2 point in physic factor. I then upgrade the physic factor. The charm gives a bonus to the rewards from the guild quests.
I usually make the free character a Dark Elf mage so they can get Druid early. Druid has a useful AOE spell.
Usually give them the Life Power sex trait for the sexual healing. This lets me do more dungeon a day without using the gems.
Side with the Mages, they give a good staff which is other wise hard to get. Usually there is some kind of crappy weapon in the shop that will do.
Set the guild quests to medium after the first day. This gives better rewards.
Do easy dungeons. The bandit den boss may be a useful slave, but otherwise can be sold. Sell any loot you can't use immediately. Rarely, there is a friendly goblin in the goblin cave. Early in the game the MC will noy a high enough Charm skill to recruit her, but you may be able to enslave her if you wish.
Give your combatants some speed classes (Rogue, Archer, Bard) so you can hit opponents before they hit you.
Do the builder tools and forge tools upgrades first. They are cheap and improve the speed of upgrading
By doing easy dungeons and the guild quests you can make the first payment, plus a quite a bit extra.
I've played to the end of the current content several times, trying out different races. Seraphs (female or futa), dragon kin, and orcs have good unique classes. Haven't played a dwarf yet. The elves and the fairy can get the Druid class which is VERY useful. Fairies die easily.