The gathering professions are great for money. Crafting can be great, but it takes a huge investment (multiple leveled up for cross-class skills and time spent gearing) to make the big money. Even so, you can make a bit if you're smart about it and find the right niches, even without being fully leveled with all the cross-class skills. I made a good amount from selling leather and a few items favored for glamours while leveling leatherworking.

I've made a lot of money running Aquapolis (the treasure map dungeon) with friends. This has been my fastest money maker, but people are usually too busy for it.

I've made a lot of money selling excess grand company seals (by buying things with the seals and selling them on market). This can be done with most of the currencies. Anytime you have the option of buying things that can be sold on market, check out the market rates and make sure you spend excess for the best selling stuff instead of capping the currency. This is my most reliable money maker.

Some dungeons can be soloed at higher levels and have rare materials that can be found in chests there. You can make some money selling those materials. 'Fine wax' from Haukke manor is one example. On my server, they often shoot up to 20k+ on market. I could get probably 10-15 an hour, but at that rate it would saturate the market, so I just sell a few here and there.