Before anything else, understand that I'm advocating a stress-free battleground environment. These aren't the rated battlegrounds. These aren't arenas. Battleground grinds for honor should be fun, another means to enjoy the game. While I don't condone ruining the experience for your fellow players by playing poorly -- and by poorly I mean whether as an obnoxious armchair general, a road fighter or an AFKer -- there's no reason to take it so seriously. This brings me to my first survival tip.
Unlike deaths in any other area of the game, battleground deaths are largely inconsequential. In arenas, a death is pretty much permanent and often directly leads to your team's defeat. In dungeons, raids and even questing, deaths burn a hole in the pocket as well as waste everyone's time with corpse runs or rez resets. Battlegrounds are pretty unique in the sense that players don't have to treat deaths as a game-breaker. Character deaths are part of the process. I will even go so far as to say they're part of the fun.
Taking away the gravity of character death also takes away a lot of the pressure. This doesn't mean I play recklessly and carelessly, though. Every second I spend with the Spirit Healer is a second spent away from a flag or tower. Every second I spend dead is a second that could have been spent dealing a killing blow. Basically, I hate dying in a battleground just as much as the next guy -- probably more -- but I understand that it's not going to impact the game in the same way as it would in other areas of the game. This allows me to play at a more relaxed pace because there's a much larger room for error for individual performance.
Of course, unlike dungeons or raids, there are clear winners and losers in a battleground match. But unless you're pursuing achievements such as 100 wins in a battleground, losing really shouldn't be a big deal. It will only really matter when rated games are implemented, but otherwise, you should be able to shrug it off and move on to the next game. Because you accrue honor even when you lose matches, it's never a useless endeavor. In those times when you need a victory for your daily quest, it shouldn't be too hard to secure at least one, right? Of course, in those occasions where everything just can't seem to go your way, however, you can always ...
Take a break
The beauty of pugging is that you can play at your own pace. The beauty of pugging a battleground is that you can stop any time you want. As opposed to dungeons or raids, leaving a battleground in the middle of a match or going AFK for a while without telling anyone won't have disastrous consequences. Nobody will take it against you and you won't gain a reputation for being a terrible party or raid member -- not unless you make a habit of bailing on teammates or being AFK for long stretches. Taking the occasional break even while a match is ongoing is excusable. In fact, I recommend it.
There are periods of inactivity during a battleground match where your full attention won't be required. At least, it won't automatically spell doom for everyone in the group if you're not entirely there. Watching over a flag while holding a sizable lead in Arathi Basin can bore anybody out of their wits. Sometimes, players crave action and unwisely leave their posts, heading elsewhere to jump into the fray. You can just as easily take a short break during these windows of dead time, but do have the courtesy of informing your team through the battleground chat. If you're guarding a node with another person, a quick tell to let them know you're not there to get their back should spare them the nasty surprise of finding out they've lost their backup when enemy players decide to hit the node.
Stand up, stretch, get yourself a cup of coffee (or in my case, some matcha), hit the toilet or even tab out of the game to tweet or feed your workers in Restaurant City. It's fine. As long as you're not deliberately handing the match over to your opponent, taking small breaks now and then is forgivable. If matches are going so awfully (or in some case, so awesomely that you aren't needed), you'll probably need breaks to maintain your sanity. In fact, if matches have been going so badly, you're well within your right to AFK out of the match and stop playing battlegrounds for a while. That's what the /afk feature is designed for.
Sometimes, you catch a really bad wave of players by queuing immediately after a loss, kicking off a cycle of being grouped with the same bad players over and over again. Taking a break from the queue can break that rhythm and sometimes get you better groups. Walking away from the game for a short while should let you shake off the bad vibes from losing games and allow you to get pumped up for another round. Take a quick nap or drive out for a Ristretto Grande Caffé Americano and Maple Oat Pecan Scone from Starbucks. A break can let you catch your second wind.