Ok, first off, this isn't a super "Ultimate WOW Gold Guide". It's just how i got the money, and it may not work for you, depending on how patient you are, and what your server economy is like. Btw this is all out of the top of my head so it may not be perfect!
Things you need: At least 200g to start off with?, 300+ fishing (375 Preferred), fishing bot (optional but it'll make it a lot faster, even though you can get banned, fishing bots are softcore imo).
People don't think fishing is a good way to get money, YES IT IS! =P
Made about 1200g off this......Normally every day I would check AH and I realized that on my server there was Greater Planar Essences going for 120g a stack? while as singles they went for 15g a piece. I used this almost everyday buying the larger stacks and selling about 10 at a time. Note: don't over auction like 20 at a time....it's better putting in about 10 selling them then reauctioning another 10 after they sell.
I know this next one is an old tactic but i must of made at least 500g off this alone. Always look at trade every now and then you'll get someone like, "Selling Primal Firex2 CHEAP". offer them something low like if they go for 30g a piece 45g for both. you'll be surprised how many times they will accept it. immedietly go resell it. i've gotten primal manax9 for 90g? resold 180g. Yes I know buying and selling is oldoldold. But this is what I did so bare with me.
All of the above was done on my spare time, any other time I was offline, or fishing/fish botting. Don't spend an hr sitting in a city looking for a good deal, check every now and then.
Fishing:
Fishing was the majority of my money, about 3000g of it.....
Since there's not many "hardcore" fishers on my server I took advantage of that and took the time to figure out which fish sold the best and which were not worth it.
I HIGHLY RECCOMEND GETTING COOKING OR A FRIEND TO COOK FISH FOR YOU TOO.
ALSO, GET THE "FIND FISH" ABILITY: Fish Zangarmarsh wreckages and loot them out of Crates, I got one in 5 min.
Now here's what fish sold from top to bottom:Best fish to Worst fish:
Spicy Crawdad from Furious Crawdad: 30-45g a stack (cannot fish bot these)
Golden Fish Stick from Golden Darter: 30-40g a stack
Poached Bluefish from Icefin Bluefish: 20-40g a stack (sells a lot better on the start of new weeks [Tuesday] )
Grilled Mudfish from Figluster's Mudfish: 10-25g a stack
Feltail Delight from Spotted Feltail: 5-10g a stack
Mote of water --> Primal water: 30g each
Note: I know there are others like the ones from Deadwind Pass, and Zangarmarsh, etc. but i didn't bother with them as they're out of the way and not worth the time compared to the other fish.
Where to get the fish!
Furious Crawdad: Comes from Highland Mixed Schools, which are in various lakes: Lake Above Stonbreaker Hold, Lake Above The Alliance Base, And the Skettis Lake or w/e.
I usually checked for the spawns every hr, gathering what i could and then going to Nagrand for Pure Water spawns (read about later).
Golden Darters: From almost every lake and river you can think of ONLY IN TERROKAR FOREST. There is actually Golden Darter Schools, but I don't reccomend farming these unless you really have nothing else to do, and none of the other spawns are up. Most of these will come from botting.
Icefin Bluefish: FROM NAGRAND. Any Lake.
Figluster's Mudfish: ALSO FROM NAGRAND. Any Lake.
Note: Both Icefin Bluefish and Figluster's Mudfish have Schools for themselves, don't reccomend farming those either. Most will come from botting like the Golden Darter.
Spotted Feltail: .........EVERYWHERE????
PURE WATER! All in Nagrand, every hr I would check at elemental plateau for these spawns near the water elementals: I gather about 3-4 primals every run if the spawns are all up. They spawn in the lakes too.
Now let's talk about botting. I usually botted overnight, and switched off between bluefis/mudfish and golden darters. i reccomend looking at the post for fish botting spots. Basically the southeast corner for Bluefish and Mudfish, and Above stonebreaker hold for Golden Darters. If you're too scared to bot XD. Sorry it's going to take you longer.
DON'T FORGET THERE'S A FISHING DAILY: Always do the fishing daily everyday, you can make so much money if you are lucky enough to get [The 2 Ring]. It will basically ensure you an epic flyer. Low chance but worth a shot as you get a chance everyday!
Remember to not BOMB the AH with ALL your cooked fish!!
The only time you should put more than 5 stacks of the same fish at a time is on Tuesday when the raid instances are reset and theres a large demand for cooked fish.
That's pretty much it, hope I didn't miss anything. Enjoy!