I've chosen Sorceror and am on Dromund Kass at about lvl12 now. I solo'ed the two Heroics on Korriban once I got Khem; they weren't a problem, so I think I might try doing the same with the Kass ones once I get towards lvl14/15. If they're too hard to solo then, I might try a group as I hopefully should have the basics of fighting down by then. I'm slowly getting sucked into MMO-land, I think...
DK has two Heroic 2+ that you can solo once you get to level 14, but they both have bosses that can be kind of rough. The second one can also become a real circus if there are a lot of people in the area. There are also 2 Heroic 4s and one Area Heroic. You'll have to group for those.
Couple more quick questions, if you have time, please!
1) how do crew skills work best for FTP players? I can only pick one skill per crew member, so I've picked Treasure Hunting for Khem (was going to pick Artifice as he gets a bonus on that anyway, but couldn't see how that would be any use given he wouldn't have anything to use it on, right?). Am I doing it right? What sort of missions should I send him on? Money, Gems or Gifts? i.e. what are gems used for and is the affection bonus for collecting gifts particularly worth anything?
That's not quite exactly right. Normally you get three skills per character, but only one of those skills can be a crafting skill. F2Pers just get one skill.
Normally, it works like this: there are three types of skills: crafting, gathering, and mission gathering. Crafting is self explanatory. The gathering skills are for mutually gathering the materials out in the world. There are nodes about the worlds that your companion gathers materials from. If you change your map to show resources then the corresponding nodes to your skill appear as little asterisks. Lastly, the mission gathering skills are for other types of materials that you send out your companion for a certain amount of time and they bring back materials and schematics--or gifts if you go that route.
Each crafting skill has a gathering and mission skill that goes with it. To find out what goes with what, just do an image Google for "swtor crew skills chart."
But since your only limited to one, there are several ways you can go. You can do what I suggested to J.
up thread and take biochem. Even if you have to buy the mats off the GTN, making your own med packs and stims will still be cheaper than buying them from vendors, and they'll be better quality.
Secondly, you can just take slicing. Gathering wise, you'll just crack safes as you travel which just turn out credits cases. For the credits alone it might be worth it. You also can run the slice tech parts missions. These turn up the materials and schematics you need to make augments, both of which you can sell on the GTN for a lot of money. Or you can save all the Willpower ones in your bank and take Synthweaving later to make them. Since you have such limited bank space, I would just level the skill to 50, and just save the 50 willpower augment schematics.
Augments also sell for A LOT of credits. (Some of the rank 27 purples go for millions or even 10s of millions.) So if you have room to spare, it might be worth it to save some of the other schematics you find.
Keep in mind though, that you'll only get the schematics upon getting a critical mission completion. Which is really rare. So if you do decide to go this route, I would just concentrate on getting the credits until you get Andronikos (on Tatooine). Luckily he's tied with T7 for best slicer in the game.
The last suggestion is to just take a mission skill, Underworld Treading and Treasure Hunting being the best two choices. With those you can just put the stuff you get back on the GTN and keep the companion gifts.
There are two problems with this. First, you'll have a lot of stuff to sell and you are, of course limited to how many things you can post at once. Secondly, all those companion gifts take up a lot of bank space which, again, you're limited to. However, if you wait until you have all your companions and then you can just hand the gifts to the appropriate companion as you get them.
2) where can you spend Commendations? I have a good number of Korriban ones and a couple of Dromund Kass ones so far. Is it worth saving them up for better stuff later in the game or spending them as you go along?
The specialty vendors are usually in the market area of each planet. There's also a rep from each planet on the fleet in the Supplies market area.
And, no, there's no reason to hold onto them. Since you can only spend them on the appropriate planet for equal level gear (blue quality mostly).
Some people like to always take the comms as rewards. Then try to find as many shells as they can for them and their companion and spend the comms on mods--or at least just for companion and then take the gear rewards from doing heroics/flash points.
If you do this, it's good to note the formal wear is an easy to obtain social set. You can buy them from the social vendor in the DK cantina. There is a dress and tux (right up your alley) set of five empty shells (head, body, legs, feet, and hands). I think you need to be social 1 to use them though, which is only like 10 social points (or three conversation rolls). You can usually get that in one group.