Do you ever wonder how some players have so much extra gold?
Well, They just know how to do it more efficiently than you. The same reason why people level faster than others applies to gold farming. There are more than the two ways I personally use to farm gold and will show you. Gold farming is tedious, so have something you don't get bored with to easily.
First, when starting on a new server or just wanting to be Financially stable on this new character, pick you two gathering trade skills, I find that the Herbalism and skinning are great money makers. Herbalism can easily make you money once you get into your 175+ herbs, while skinning makes you money almost immediately.
Next, farming primals are a great way to get money as most sell for 20 g or higher. Air usually sells for the highest at around 26 g on most Servers, a good place to farm this is in shadow valley near netherwing field. Fire is also a good primal to farm and usually sell from 22-24 g on most servers, farm primal fires in blades edge mountains on the border to nether storm. Primal manas is also a primal worth farming, which can be found in nether storm by killing most of the creature there, and sell for around 20 g. Farming Primals is a great way to make flying mount money or repair money at 70.
Gold making in world of Warcraft comes in various forms. I would highly suggest using these two simple techniques, even though there are countless.