You should really utilize whatever avenue of trade is available to you if you want to maximize profit.

Every once in a while, people standing around the AH will ask if you have x amount of x material. If you have some, why not ask how much they're willing to pay for it? Might make a quick buck or two.

With regards to Auction House pricing, first, look at the prices of the items that the Stranger merchants are selling. That's your baseline price. Then, do a search for the name of the item you're selling at the AH. Use the baseline price and the AH prices to determine what price you'll put on items to put up on the AH. You can probably go higher if the item in question has a Unique Variant (UV).

As for which items to sell, go through the wiki for a bit, and see which equips have alchemy lines that go to ★★★★★. The ★★ versions of those are more likely to sell than equips that have alchemy lines that end rather prematurely. Popular lines are the Wolver line of helmets and armors, and the Owlite shield line (of the Magic set line). A possible exception is the Cobalt set line, because the recipes for those are always available at Kozma the Spiral Quartermaster in the Bazaar.

P.S.: Haze Bomb