Well, money isn't terribly hard to make in this game. Doing dailies nets a pretty big chunk once you reach level 50 and have some decent gear.
As far as crew skills, I recommend underworld trading and try to run as many metals missions as possible for Mandalorian Iron. Diplomacy is another decent option for the Radioactive Paste. Slicing is another decent one for both the Advance Neural Augmentors and the max level missions that come from the lockbox missions.
Those are all mission skills, so if you take all 3 of those, you won't be doing any actual crafting, but if all you want is money, those are probably the big 3.
The richer people on the server are probably Cybertech's, Artificers, and Armstech people who can clear all the toughest operations and who's guilds let them reverse engineer all the mods for guild use. Once those guys have the schematics, they make big bucks selling the mods, or charging other players to make them.
He speaks the truth. The most profitable form of crafting is to RE specific drops (whatever the BiS tier of Hilt/Barrel and Armouring is at the time). Formerly the moneymaker was Campaign Hilts/Barrels Armourings now it's Dread Guard. But remember, there are no Skill using tanks in the game, so Patron gear is a waste. I think Dread Guard gear minus patron is generally a safe bet.