Erm, try to avoid fights as much as possible when playing (it sounds silly, but bear with me here). They're luck-based and half the time you won't win, even if you're better than the other person at clicking and aiming. Try to find good chest routes on maps and know the locations of tier 2's so you can get good armor and weapons without having to fight people. This way, you can survive until deathmatch without risking death from other people and all you'll have to do is kill 1 or 2 other people to win.
And if you really want to win, find chest routes on maps that aren't played often and then try to get them voted. This way, you'll have routes on maps that no one else does and you'll be a lot more likely to have way more gear than everyone else does and victories will come even easier.
But as for getting better at PvP itself, I don't really know what to say. Just click and aim, that's really all. Use rods, because if you don't other people will destroy you with the unfair hits they get from using them. Try to use Flint and Steel and your bow when fighting someone before just rushing in with your melee weapon so that you can deal damage to them and even if they get luckier with hits, they'll be lower so it'll be somewhat more even. Also, if you're able to figure out how to do it well, block-hit (it is possible in 1.8, it just looks weird).
Getting cleaned up, chased, and teamed on are basically all unavoidable unless you play Solo SG (which is dying, it has as many players as Survival Bingo does). Also, to avoid getting chased off of corn, don't equip tier 2 armor you got from the chests before you have a weapon, because people will target you for it.