Honestly, the best way I've found in game to make money is through a combination of smithing and enchanting. Stock up on soul gems, iron ore, and leather. Make an iron dagger, enchant it, then sell it, then repeat. However, if you really want to start rolling in dough, there are certain enchantments that are worth significantly more than the others. The one that most comes to mind is Banishment. I was able to combine Iron Ore, Leather Strips, and a petty soul gem to make something that sold for over 1000G with no perks in Speachcraft. Lather, rinse, repeat. The only downside is that you'll rapidly find yourself outselling the vendors, even if you purchase every iron ore, leather or leather creator, and soul gem you come across (even with Grand Soul Gems you will make a profit per dagger).