(Warning: Very minor spoilers about the Sith Inquisitor story but nothing that will ruin your experience. I can't, however, guarantee the spoiler free status of links so beware!)
I have done something terrible, something absolutely heinous and I feel awful about it. I didn't for it to happen, events conspired against me so as to make my final course of action inevitable. It's really not my fault, I mean he would have killed me wouldn't he? It happened on Balmorra, a planet recently conquered by the Sith Empire deep within the galactic Core Worlds. I'd been sent there by my Master to retrieve a powerful artifact but upon my arrival I quickly learnt that this was no pacified planet. A brutal guerilla war had been ongoing since the Republic's withdrawal as the local population was less than chipper about have a bunch of sadistic force users as their lords and ladies. On top of, judging from the state of the place, it was pretty clear that the Imperial Governor had reduced trash bin collections to once a fortnight. Daily Mail readers would be incensed by the whole thing. So being a responsible member of the Sith Empire I resolved to clean up the mess my fellow Sith had created, bring an end to the conflict and pick up that artifact along the way. They'd call me Runz the Peacemaker! Well that's the plan anyway.
You see I'm no conventional Sith. I am Runz, a Sith Assassin with a heart of gold and an eye for the ladies. Oh I talk big about crushing my enemies but that's mostly to impress my Dashade companion. You see I am secretly a member of the Revanites, an outlawed cult within the Empire that believes that Revan's mastery of both the light and the dark sides of the force is the true way and will bring both power and peace to the galaxy. Really I didn't even want to be Sith, I'd originally set my sights on being a Jedi Sage, but all my friends were being Sith and I just wanted to be one of the cool kids. Funny, this story seems to sound exactly the same as the story of why I started smoking, oh hum. So I spend my days trying to advance myself in Sith society, pleasing my somewhat twisted master whilst attempting to maintain some sort of moral code. It boils down to this;
Killing defenceless civilians is bad.
Killing Rebels/Republic soldiers is fine if they're on the field of battle, they knew the risks.
Killing Jedi is justifiable if they conflict with my goals and will not stand aside, but I won't go out of my way to start a fight with them.
Killing fellow Sith is completely acceptable as they're a big bunch of arseholes who will kill me given the opportunity. Most of the time I don't have to go out of my way to start a fight with them, it just happens and shouting "SAME TEAM, SAME TEAM" appears to have little effect on the situation.
A TALE FOR THE AGES
You'll notice that so far I've mostly been talking about me and my character and not very much about the actual game but that is for one very good reason; the story of your character is inextricably linked to the game and it's mechanics. Many of the game's mechanics are used to drive the story, and the drive of the story propels you through the more traditional game mechanics that might otherwise be somewhat uninspiring.
Let's be very clear and get this said right at the start; for all its glitz and glammer SWTOR is essentially another WoW clone, it is another hotkey MMORPG based on statistics, gearscore and RNGs. There's no escaping that fact and aside from some elements of gameplay it is not a player skill based game. Granted gaming basic skills are still required, such as not standing in the fire and being able to position yourself behind the enemy to backstab but, much like WoW, a lot of your performance is more likely to be based on how good your gear is and how you've built your spec. Those with greater spatial awareness and faster reactions are more likely to be better at the game but these personal abilities are not essential to have in great abundance to play the game well. As long as you have an awareness of where to stand and what your abilities do, your spec and your gear will likely carry you through the rest of the way. This is generally how MMORPGs work, we all know this so this will unlikely be a surprise to anyone.