With any profession, you can make decent money by selling to people's alts. You need to be able to make the regular item, reverse engineer until you get the proper blue, then make those and RE until you get the proper purple. Then you have to be able to sell it for enough profit so that its worth your time. This means, for the most part, no buying mats off the GTN.
Levels 25-45 are the best options because at lower levels, people are hesitant to spend much. At higher than 45, people should just be saving for better than player crafted. When selling to alts, it has to be very affordable so you need to do high volume.
These are items that anyone can potentially sell to alts:
-Purple Implants (this is what I do)
These you can sell to anyone of course:
Low level stims do not sell, at least on my server. You'd think they would but they don't.