I have found that money is easier to get than in previous games, especially early on.
Some suggestions that I have found useful
1.) Raid Dungeons. Not only can you sell loot (I find light hide and leather armors give a good weight/profit ratio) but also there is usually a couple of hundred gold in coins lying around the lower level dungeons (in money bags, chests, corpses or loosly on tables).
2.) Sell potions. Lots of money in potins, I usually keep the health/stamina/magika ones but sell everything else (incl. increase health for 60 sec or restore x health over 300 sec etc). If you dabble in alchemy you can make potions and sell them for good money. Ingredients are easy to get in the wilderness (plants, butterflies, mushrooms etc).
3.) Farms - many farms will guy mundane vegitables (not ingreediants, these count as food) for more than shops. For example outside whiterun there is a farm that will buy potatoes for 1g a piece and cabbage for 2g a piece. Not a lot individually but considering there is loads of these not only in farms (that respawn) but also in guilds, dungeons, houses etc
4.) Chop wood - might not be the most excisting but some decent money to be made. For each session you can earn 30g I think (get 6 pieces of wood at 5g a piece). Takes about 45 sec or so to complete each session? If you have the patience easy to make some money, especially in the beginning. Tip: Chop wood my a lumbermill such as Riverwood and sell to the lumberjack.
5.) Sell jewelry -> lots of rings, gems and necklaces around that are worth a fair bit of gold. IF you are not big into enchanting jewlrey this can be a good source of gold
Hope this helps somewhat