One thing to remember is that if you want to make a lot of money don't try to sell each item for a huge profit. When I was an architect in SWG I had other architects complain constantly that my prices were too low. They wanted to make a weeks income on a few sales. Make an hour's income on 200 sales and you'll get repeat customers, referrals, and more money than you can spend.
Also, let everyone know that you'll make anything for the mats (though you don't have to refuse tips). People bringing you materials is by far the best way to acquire them. Depriving the world market of their credits is a small price to pay. Again, people will come back to you and send their friends.
Note - this does not work for Sith. Sith must be rude to everyone and refuse all forms of help as a sign of weakness! This only applies to Republic crafters. You have been warned!
Crafting is really accessible in TOR, so I don't see the same situation as SWG had working well. People can all make the same quality and there isn't that much barrier to entry. So, buyers will just go to the GTN and buy the lowest priced stuff. GTN = Vending Machine. Unless you are actively trying to control the economy, undercutting by large margins will typically have negative effects to all sellers.