Find yourself stuck with no clue where to go? Many listings have tips that will appear if you click them; even better, many npcs and places can be located on the map. "/pathfind" is the command, but there's also a button you can find labelled "locate". Not everything has a locate button, but most quest npcs do.
Not sure what to do next? Open your quest listing and check the campaign quests. You might've skipped one or it might not have popped up on your quest tracker yet. I've noticed these quests, along with being a pretty good storyline on their own, are a good guide to moving through the world.
We all know what vendor trash is, and Aion npcs even have that handy "sell all misc" button for it. But for those things that don't sell that way, look them up at aionarmory.com and you might find you have something useful. (Those fluxes, for example, sell pretty well.) White armor/weapon drops should probably be vendored, but you might get more for green items at the marketplace.
Gather as you go! It doesn't take long to hit areas where the gatherable items' skill level is way up, but if you hit a gather point anytime you see one, not only will you have stuff to vendor or market, you'll get that skill high and be able to gather really worthwhile stuff sooner (like quartz, crystal, silver, and amethyst, which are uncommon gather points).
If you plan to craft, it's worth it to work on the extract aether skill too, since a lot of weapon/armor recipes require the aether powder. Plus you can transmute aether powder into hard-to-find gatherables for when you need just one more.
Speaking of crafting, it's also worthwhile to explore those recipes on aionarmory.com. Some crafts are relatively cheap to master (alchemy) with equivalently low returns, while others (handicrafting) cost a lot to level up but can pay big dividends when you get to the green recipes. Remember that you have an account warehouse, so it might be worth it to outfit all your toons from one crafter on each side.
The last, best resort for news when the sites and servers are down is twitter. aion_liv, aion_ayase, aion_amboss, aion_xaen and a few others all post frequently and typically blurt newsbits before the sites Also, right now there's a bug on the official forums that prevents dev-as-dev posting, so what forum posts they make are at aionsource.com's forums.