1st: Join the thieves guild and peform reapeatble quests known as "jobs". Some of these jobs can be pretty challenged if not skilled in the arts of stealth. Therefore i would recommend to take "The burglary job" from Vex and "the numbers job" from Delvin. On "the burglary job" you are supposed to steal an item from a house, this is easy during daytime because most pepole are at work. On the numbers job you are supposed to "edit" some notes in a ledger book at a random bussniess. This is also easy, but make sure that the shopkeeper is out of sight or he will call the guards. The reward for each jobb is 100-500 gold depending on level. There is also a quest called "No Stone Unturned" ( link here ---> http://elderscrolls.wikia.com/wiki/No_Stone_Unturned here you are going to find al the 24 stones of barenziah. I will not go on details on this so please check the link. The reward for this quest is a permanent perk called "Prowler′s Profit" Its increase the chance of finding jewels such as diamonds, rubys, emeralds, etc (soul gems not including) in containers. I recommend to finish this quest early so you can gather a lot of gems.
2nd: Once The Dark Brotherhood questline is completed, you will recieve a quest called "The Dark Brotherhood Forever" This is also a repeatble quest wehere you are going to kill a random target. Oh and don′t worry these target spawns at the start of the quest, so you will not go out and kill pepole who owns stores etc. The reward for every contract is a leveled amount of gold up to 1200 gold.
3rd:This place is one of my favorite underground cave. Blackreach is ancient dwemer ruin in a huge underground cave filled with giant glowing mushrooms. The celing of the gave glows with blue lights and massive glowing vines hang down. It′s like Pandora, the planet from Avatar! For more info on Blackreach see this link ----> http://elderscrolls.wikia.com/wiki/Blackreach. Geode Veins are unique only in Blackreach and has a blue glowing appearence. When mining these you can recieve soul gems (from petty to black) and therefore it′s a very good source for money making, also for you who playing as mages these is a good source. Although this is depending on your level. At level 5 you will most get petty soul gems. At 50+ you will start to recieve black soul gems.
4th: This is for hardworkers! Get your smithing up to at least level 90 and go for the daedric smithing perk. Daedric armor is the best armor in the game (even better than dragon armor) and therefore it has a high value. You are going to need ebony ignots and daedra hearts. See this link for more info ---> http://elderscrolls.wikia.com/wiki/Daedric_armor. Also improve and enchant it for a higher value!!
I will come with more ways to earn money in the future, also if you have any comments or questions please share them.
