You can make well over 5,000 gold before even killing the first dragon. You can find these potion ingredients mainly in mountainous/forest areas.
If you don’t want to make your go experience go down, don’t do this part, as you must go into the town where that person’s is house again. Go back to the town that the person’s house is in and draw your weapon, then sheath it. A guard will come up to you and say “It’s time to pay for your crimes. What say you in your defense?” and select “I submit, take me to jail”. Sleep in the bedroll in the jail cell and you will get to keep your money.
Complete the dark brotherhood; it gives you 20,000 gold.
Do not fast travel. Instead, walk everywhere. You will run into tons of animals whose pelts you can take. Make sure to craft your pelts. Use the tanning racks to turn the pelts into leather; craft the leather into leather helmets at the forge; improve the leather helmets at the crafting table. You will get tons of money and level up really fast.
If you smith weapons or armor, make sure you improve the quality (make armour/weapons fine, superior, flawless, etc). This much improves the value of said item, or otherwise simply makes it a more practical piece.
Try not to sell things you want like spell tomes, lock picks, or anything of that sort. If you don’t want dragon armour, sell the dragon scales/bones. They usually sell for a lot. (Scales are worth 250, bones are worth 500. ) If you’ve got some weapons or armor with no enchantment that’s worth a good amount of money, that you don’t need, enchant it and then sell it, it then sells for a higher price. If you pick up extra/other armour that you don’t need, sell it to one of many blacksmiths in Skyrim.
Every 24 hours gives you 100 gold; it’s not much but at least you don’t have to do any work.