Now, it turns out the way you earn the top PvP gear has changed since I last cared about arena and it's actually a lot easier to work things out. There's all sorts of weirdness with personal ratings and team ratings and 4 different ones of each (2v2, 3v3, 5v5, rated battlegrounds) but it seems like that stuff is mostly for achievements and matchmaking. What it comes down to is you have a cap on the number of conquest points you can earn each week. This cap is based on your highest personal rating from a team that played a game the previous week. (So if you have a high rating you can earn points faster than someone like me with 0s across the board.) Then each time you win an arena match you earn a fifth of that cap. So five arena wins and you're done for the week. Only have time for one game? Fine. If you win, you get a fifth of your cap. Rated battlegrounds are worth even more, with you earning a third of your cap for each win. You can also earn a trivial number of points for doing the daily battleground but when an arena win is worth up to 600 points and the daily is worth 25, well, it's just not worth doing. Even for me with a 0 rating, I get 270 points for an arena win and the same 25 for the daily.
Someone made a chart showing how the cap scales with your rating which I hope to embed here.
Clearly you want to up your rating by playing a lot of games at the start of the season (oops!) and then just play 5 wins a week to scoop up gear. By the end of the season you want to play a lot again if you're pushing for a title or whatever they give out now. But for now, clearly, I should just find someone to play 2v2 arena with and earn a few points.