Whats the best or fastest way to gain coins? Ive been doing missions and such but Im wondering if theres a better way to get more coins?

try exploring the trollsblight caverns and opening as many chests as you can. i've been told this is one of the better ways to get plenty of gold.

see: guide to making gold and the guide to mission pets and missions

Missions are generally considered as one of the best/easiest/fastest ways to make gold. Once you have all six of the mission slots unlocked so you can run six at once, and both Esior and Saerielle's missions accessible (and... do the higher difficulties of mission have to be unlocked? I swear that was a thing we had to do way back when but it was so long ago I can't remember if it actually was or not) and mission pets that can get Exceptional results if not every single time than close to, then it really starts to add up (you can see our study into the payouts of missions here, which has a google doc to mission satchel contents linked here)

Other things to do are selling all the equip drops you get from fighting back to the site- they aren't worth much at lower levels (being low leveled and low rarity both), but they're something.
If you'd asked two weeks ago we'd have said 'do rounds of the fest zone' but it's closed now sadly- a single round of grabbing zone chests+selling enemy drops can make quite a lot of gold. Just have to wait for summerfest in a few months to get to do that, I suppose.

And trollsblight chest farming has already been mentioned.

Alrighty thanks you both for the tips!!