pro-tip; if anybody is hard up on making money let me tell you how i became rich. these are all things it took me like 60+ hours of playtime to master, if youre in a rush to finish the game this shit might help you out, but it could also take some of the fun of the game away, so i wouldnt recommend it lol. anyway
*SPOILERS*
enchanting and blacksmithing are the key to making thousands of gold. buy the house in whiterun if you havent earned any property from quests or havent joined any guilds or anything that let you have a bed and place to store your shit. looting everything you find and selling it to merchants helps out in the beginning, to get your house, but after awhile its just a waste of time
get into the habit of buying as many soul gems you can afford from every merchant you come across, and carry a weapon with the enchantment that takes an enemy soul and puts it in a soul gem. or use the spell. stock up as many soul gems as you possibly can, and kill everything in your path while doing quests, wolves, bears, foxes, rabbits, EVERYTHING lol. those critters will fill up your petty soul gems and common ones. get into the habit of buying every silver ore you come across, and save every silver and gold ingot you find, and save every gem you find (garnet, sapphire, diamonds, etc).
so all those hundreds of iron daggers you make from blacksmithing? enchant them, that simple lol. find a weapon that has the life siphoning enchantment, disenchant it to learn it, and enchant all your daggers with that shit. its the one that ive found that sells for the most. or use whatever enchantment you have that is worth the most money (select an item, select a soul gem, then select the enchantment, and go through which enchantment changes the items value to the most, that simple). if the merchants run out of money or youre over-encumbered just store all the excess items at your property till they get money again, dont trash anything
all that silver ore and gold ore and all those gems you got? why not just sell them to a merchant for money right then and there? well you could but you make a shit ton more money by using blacksmithing to make gem studded necklaces and rings and shit. save all of those cause they weigh almost nothing, then enchant them with whatever enchantment is worht the most money. ive found that the increase sneaking enchantment makes for great cash. i can enchant a necklace with like +26% sneaking and then sell the necklace for 1000+ gold. think about that. a gold ingot sells for like 60 gold or something shitty, a diamond sells for like 400 gold or something shitty. a greater soul gem costs like 200 gold. but make yourself a gold diamond necklace, its worth like 900 gold to a merchant. enchant it with sneaking, suddenly its worth like 2000 gold. spend 200 gold and turn 460 worth of items into like 2000, lol. even better if you came across the soul gem in a dungeon for free
well thats all i can think of right now. before i started doing this i only had like 100-5000 gold at a time. now im sitting on like 160,000 and dont even know what to do with it lol. also making necklaces increases your blacksmithing. and enchanting all that stuff brings up your enchanting skill
oh yea and always sell everything one at a time. im not 100% on this but im pretty sure the game works by when you sell an item its like a speech check. the gold you get depends on your speech skill. so lets just simplify it for imagination sake, you sell 7 steel boots all at once, that is 1 sale, and counts for 1 speech check. it saves you time, but if you sell 7 steel boots one at a time, that is 7 sales, and counts for 7 speech checks. thats 7 times that your speech skill goes up a tiny little bit vs. only 1 time. the higher your speech skill the more money you make. i think my speech is like 74 right now, i wouldnt be nearly as rich as i am now if i didnt talk to as many npcs as i could and sold everything one by one. also, there are amulets that let you get more money from merchants, like +10%, and the thieves guild hood gives you +15%, always equip those before buying and selling to get better prices
all in all this is a nice little circle that helps you: raise your enchanting, raise your blacksmithing, get tons of gold, and help you save time by not having to loot every single thing you come across and walk a half a mile an hour while encumbered everywhere lol. ive found its pretty efficient. when your skills are low it might seem counter productive; spending tons of money on iron ore for blacksmithing and silver ore and soul gems, but after awhile you start profiting like crazy