A lot of people seem to have issues with making even a few gold in Guild Wars 2 and I hope with this "guide" it will help people understand different ways of making gold and how to keep making gold in new ways as the game progresses through it's lifespan.
One of the easiest ways to make gold in droves is from the global Trading Post. The TP is global across every server. Each server doesn't have it's own Trading Post. When you set an item up for sale then someone on Underworld or Jade Quarry could buy that item from you.
To start out simply and to make a bit of silver here and there is to find an item that is in high demand. Look for something that a lot of people have put in orders for. Obtain that item at the lowest price possible and in high amounts. Once you have that item in bulk then resell for even higher than you originally bought the item for. Depending on the item you will make back in profit more than what you shelled out to purchase or obtain that item for.
Example # One
When Unidentified Dyes were 2 silver each I would buy them in quantities of 50-150. Of course when dealing with uni dyes it's a gamble because you don't know what you'll receive when you open it. I got very lucky with this venture and ended up buying over 10,000 dyes in a span of 2-4 days. I made back in profit 300-400 gold. I had gotten several Abyss, Celestial, White, Black and Midnight Ice dyes which sold for a low amount then. I was able to make massive profits. With all of the common and masterwork dyes I got I would forge them to get even better dyes.
The Lesson of # One
I got cocky with my uni dye purchases and put everything I had into one final bulk purchase of 15,000. While I still got some very nice dyes, I didn't get nearly what I hoped and in the end lost 400 gold.
So while I was making hundreds of gold a day I also lost hundreds of gold in less than an hour. The lesson to be learned is that you do not get cocky with the TP and you do not stick to doing one thing over and over. Mostly due to my spending and buying I caused Unidentified Dyes to hit 10s a piece. I also caused Abyss Dye to raise to nearly 13 gold each as well as the other dyes.
Dungeons are a fantastic way of making additional gold and silver. Not only do you get massive amounts of EXP at completion but you get loot from chests and boss drops. The Bag of Wonderous Goods is great too since you get an additional 3 tokens, drop of karma and a bag of gold which may or may not have 1 gold to be given when opened.
Dungeon runs are also a great way of getting influence for the guild which gives us better upgrades that benefit everyone.
There are countless other ways to make gold. I won't mention farming because that's a given. I'll add more to this guide as I think of better stuff.