Some good tips here (also some silly ones). There's no one best way to make gold, and it takes time to get a big bank. The most valuable items are always rare items sold in guild stores. Go to a busy place like Wayrest or Reapers...wheremthe best stores are. Look at those guilds highest-priced items. Find some that you can farm....farm a stockpile...then join a guild with a trader and start selling.

For new players, I find motifs to be ideal. There are 20 styles in the game with 14 purple motif pages, each which sell for $10k-$100k depending on rarity. Look at the prices of these in guild stores, then look up how/where spendy ones drop. Then farm for them. When you get a stock, join a guild with a trader (expect to pay $5k-$10k per week for selling privileges.)

I have several routes I've done at various times. If you have thieves and dark brotherhood, I used to do the daily in dark brotherhood for a shot at a motif, then the thieves repeatable for a shot at an abahs watch motif, then the thieves daily for a shot at a thieves guild motif. I'd also make $3-$5k from the stealing and quests. I'd get a motif most days...so it doesn't take long to build up a motif supply to sell. Other farms might include Gold Coast world boss dailies, wrothgar world boss and delve dailies, etc.