This is a very simple and early look in to the Ranged Heavy Armor classes for SWTOR. I didn't get to level both classes to Lv50 but I managed to scrape them past the first Act (32+). This guide will cover everything that I've experienced so far; Flashpoints, Heroic quests, PvP, and solo grinding. As a disclaimer, I'm mainly talking about Commando / Mercenary classes. This is not a tanking guide.
BASICS
Just so you know, you chose the right class to do a shit ton of damage in spurts. Absolutely change preferences up after the initial cut scene. Make things comfortable to your play style. For me, I added every available quickslot (left right and bottom center). I also played FFXI, so the demand for macros and how to trigger each macro translated to SWTOR. Key bindings is essential to play style. Figure out what key bindings is most comfortable with you (after I explain it of course), and run with it. While you're tweaking your UI, add the targets HP numbers (to show exactly how much health each target has). This is a major difference between using Tracer Missle and the Pew Pew rocket that knocks normal mobs down. While you're at it, turn on the allegiance indicator, for cut scenes and sweet Mako loving.
As far as gear is concerned, don't harrass yourself in to focusing on gear during the early levels (anything before tatooie really. This is where anxiety over your speeder license comes in to play). Just focus on Aim, Power, Critical, Surge, Alacrity - in that order. Aim because its your everything. Power because it raises your base numbers on healing/damage/elemental damage. Critical to raise the chances of doing +50% damage. Surge to pretty much raise the critical damage. Alacrity (really useful with relics fyi), to reduce the casting time for all abilities.
When solo grinding, please keep in mind Death From Above should really be used as soon as you have it - especially on 4+ mobs. When you're faced with a situation where you have a Strong mob and 1-2 normal mobs; sticky the Strong (unless its a melee because it runs towards you), then Full Auto/BH equivelant the normal with Pew Pew rocket x1 and/or tracer missile to kill it off. Any chance to stun the Stronger mob helps you out to deal with trash mobs. The faster you get rid of trash, the faster you can focus on just one target. It's common sense, really there's not a lot to either classes. You're given a lot of tools, some you use way more than the others.
PVP
This is what I'm really really good at surprisingly. I will try to post videos as I learn how to record and edit them. PvP in SWTOR is really broken at the moment. At any level a Trooper/Bounty Hunter (from now on I'll call them Gunners) can really dominate in PvP. I do not suggest starting to PvP until after you leave the Capital Cities, you have a limited amount of tools that kind of hinder your enjoyment for warzones. Since I'm focusing on Bounty Hunter, I'll use these their terms (because every classes mirrors each other). I mainly roll with the armor piercing cell since there's a general refund on the amount of heat/ammo you receive from critical hits.
SKILL TREE
http://www.torhead.com/skill-calc#300McZMIkbRbdRkfzZf.1
Lets get this out of the way, at the moment, this is ideal DPS build for any Mercenary / Commando. And a lot of the moves are severely broken in our favor. The above focuses on the middle column. Left side is healing (which after 30 seems viable as a PvP healer and can really sustain itself against any DPS for a while). Right side is the "PvP' spec.
The most important attributes are taken from each side. One of the most important thing to take from this is Vent heat +16 and Alacrity +4. Alacrity basically gives .4 off of Tracking Missile / Gravity rounds. Which is minute, but you'll end up stacking gear with this anyway. Vent heat on the other hand is literally a free 25 heat move (yes its 24, but you recharge it anyway). After you max out the center tree first, focus on vent heat. You run out of heat on Elite mobs (golden star) more than the demand of alacrity in higher levels (you have gear to supplement this).
So lets focus on the main center tree and why its so important to rotations. For the most part, focus on damage before focusing on other shit. ideally at level 20 you should have Gravity Round / Tracer Missile. And at Level 25 you should have the additional stack item right above that selection. And again at level 30 you should have a move that increases your Rail Shot / Trooper equivalent. In reality we're not focusing on moving away from this tree until level 41 (or after your last perk).
Since everything after 40 is pretty much stat improvements, lets focus on something very important, rotations. Rotations are fairly simple when you think of it out loud. Pre-40 you're stuck with just Tracer Missiles and Rail shot, which is NOT a bad thing. You're given the most powerful 1.5 second dps move in the game for PvP and PvE really at a low cost. Remember, each critical with Armor piercing cells vent 8 heat every time after 3 seconds from each crit hit.
Pre-40
In reality, you don't want to rape yourself with the amount of heat you give off from tracer missle, but fuck it, you get 1200-2600 per shot (each PvP character only has 1100-12500 max). This single move is your bread and butter. Plasma grenade for people that like to move in to crowds like retards -> Tracer missile x5 -> Rail Shot. Focus on people that are low on health, healers, and dual wield force users. Remember to use your CC move when they try to heal or they try to use a channeled move. If you're under 20, just focus on your Full Auto attack and power shots. There's really nothing you can do until your Death from Above move is up.
Post-40
Now this is always situational. But most situations dictates your target rushing to cap a target. This is pretty straightforward from now on. Full auto attack (30% chance your tracer missile will reset this and make it a total of 58% stronger than base damage) -> Tracer x3 -> Demo round -> Tracer x2 -> Rail shot -> Full auto if needed. Something will be dead after this. You'll churn out at least 12,000 damage within a given period. I find it hard that someone lives after 7-8 tracer rounds.
Key Bindings
This is the most important part of PvP - being able to react fast. It's all about comfort in this case, but just have your CC moves readily available (you can see my setup in the damage screenshots below). But really, just be smart in every situation, think out loud. Do I really need Power Shot, Area channel, Rocket Punch or a few other meh moves in my main keys? No, move that shit out and keep your main keys on your main move hand.
Targets
Low health players should always be a target, a person at 1 HP can still deal a lot of damage in PvP, whether its CC or straight damage, kill them off and move on to the next one.
Identify who the healers are. All healers have a CC move that they're really quick to use as soon as they see someone coming after them. Let them use it. After you get a few rounds in to them, CC them after 50% of their health, then finish them off. Its not rocket science to know that when you CC first, you give them the opportunity to do the same to you at a worst time. Healers are really stubborn to kill, so remember to know when to pick your battle. Plus you have your concussion charge which should always be your #1 CC before engaging (you're given 2).
Lightsaber melee really suck in this game. Especially dual wielders. You have to realize that the fact that there's distance between you and them allows 5k+ damage to get between you and them after you push them away. These are the weakest targets that will probably attract to you because you're focused on dealing damage via tracer missle instead of running around like an ass.
Trooper/BH - It's really funny to face the same class with the same specs. Again, remember to let them CC early so you can CC in a later time. If you're not given that opportunity, you can break CC and use CC right after. If you die, you died a noble death.
There's really not much to say until you get the feel of each players play style. Just work as a team and try to get a healer with you wherever you go.