Here are some pro tips for each of the warzones:
Huttball - The majority of the team should always be near the ball carrier. Always. Doesn't matter whether the ball carrier is an enemy or a teammate; either you're protecting the ball carrier, or trying to kill him. If you can get teamwork going, it's good to have one or two people in the enemy area up on the walkways so the ball carrier can pass the ball up to them, or intervene them (friendly charge) if they're a Guardian, or get pulled if there's a Sage up there. There are different strategies for pre-made groups of people that are all on voice chat working together, etc.; so the stuff I'm listing is for PUGs, or pick-up groups. Also, when it looks like your team's about to cap, SOMEBODY should be heading to the middle to try and pick the ball up again. (Stunning someone just before the ball's about to spawn if an enemy is there waiting for it also is something you need to do.)
Alderaan - Before the match starts, try to get people to either split to the sides (4 to snow, 4 to grass) or get 6 to go middle, and 2 to go either snow or grass. I prefer the 4-4 strategy. You can run between them underneath middle to defend both, and it's uncommon to see the enemy team send more than 2, and very rare to see them send more than 3, to either side; so 4 grass and 4 snow almost always results in two being captured. The enemy gets middle easily, but doesn't have time to run and stop you from capping either side, typically. Then it's just providing support back and forth between the two as quickly as possible to hold them. Remember, for the two side nodes, you can fly directly down to them after dying when you control them. (Extra speeder bikes show up on the far let and right sides in the spawn area when you control them.)
Voidstar - This one is the most gear-dependent, which is annoying. It's best to generally have EVERYONE rush one side or the other. The other team always has to have at least one person watching the other side, so if you can convince everyone at the start to either go right or left, you can usually overwhelm and get the bomb planted, eventually. Otherwise what you can do also, is have a stealth go to the other side to try and plant the bomb. Scoundrels work really well for this, because they have amazing CC capabilities. This warzone almost always results in the side with the better gear winning, though; or assuming equal gear on both sides, whichever side has a couple of healers that are healing.
What can also work is if you grab 1 or 2 people to run with you if almost all of you are on one side, so what you do is wait until the door opens for the enemy and they all drop down on the side with a ton of people, then try to "escape" with a couple people and kill the one person defending on the other side, and plant it. This tends to work well, too; but you can't just run willy-nilly and do it when you feel like it, it only works if at least 7 people are on one side, forcing everyone that just came out from the enemy spawn area to drop down on your side; so you watch for the door to open, and the instant they jump down, you leave.
Ancient Hypergate - What constitutes best strategy here varies, depending on how well-geared your team is compared to the enemy team. Assuming you have approximately equal gear, or you have better gear, you should just get your pylon each time and have 1-2 people defend it, with the rest staying in the middle and retrieving orbs and bringing them back to your base. Killing enemy players gives points, so if you can control the middle and keep killing them, you'll win by a large margin. If you're outgeared and the enemy controls the middle or they're just killing you way more than you're killing them, then your only hope of winning is to try and steal their node just before the timer hits zero.
If you have a stealth, they can try doing it solo if there's only ONE person defending the enemy node. Otherwise, go there with 2-4 teammates and try to kill or distract everyone enough for you to get the node. It takes 6 or 8 seconds to cap it, I forget which, and you have to have it capped by the time it hits zero; so starting to cap it with 5 seconds left results in nothing. You need to give yourself some time. Typically, you'd start heading to the enemy side if you're at the pylon on your side with 80-90 seconds remaining. You're going to want to run through one of the side tunnels to do this, not the middle, because if half the enemy team sees you and comes to defend, you're screwed. even if you outgear them and can kill them, it's easy to just last long enough to stop you from getting theirs. A clever team that is considerably under-geared can still win this warzone if they can capture both pylons for one of the rounds, since it not only gives you extra points for that round, but it prevents those points from going to the enemy.
Denova (Novare Coast) - For this one, the biggest point that people don't understand is that it doesn't matter what nodes you control, as long as you get two of them. Every single time you play this one, you will see a ton of people that think the "key" is to control the middle. (South.) This is BS. As long as you control two of the three nodes, you're getting points and the enemy is getting nothing. What I normally do is let all the sheeple run to south, but I go with a friend (I rarely PvP alone, I'm typically with one friend.) to the close node where you exit from the north entrance of your base, we cap that, then immediately run to the other node at the north end. (It's a triangle; NW, NE, and S; and which side you're on will vary.) A lot of the time, you can end up getting the two northern nodes while most everyone else is fighting at south.
Typically, the other team will have only one person going to their non-south node, or they'll send two but then one goes to assist south as soon as they cap it, so by the time you arrive it's one person there anyways. Then, assuming you capped the two northern ones, you BEG for support at both of them in ops chat and ask people to stop going to south. People ignore it half the time, so good luck. Another strategy here if you can't keep the nodes you get is to ping pong between them. If you see a large force coming to one of the ones you control, and there's not enough defense with you to hold it and kill them, then just run into them and die, and try to get a couple of people with you to go to the one they currently control. Who cares if they get one of yours, when you can go kill the one or two people at the one they control (south, in this case) and take it? All that matters is is you control two. I've won plenty of games without ever holding the same two nodes for more than a couple of minutes at most, because me and a couple people keep going wherever their large force just came FROM.
However, being level 14, you only have a few abilities and you'll be quasi-worthless because of it. Once you're in your 30s, you'll have a lot more utility and use from talents and trained abilities you've gotten along the way.
"VICTORYYYYYYY!" -Johnny Drama