If you're serious about PvP, I would start with as much of the crafted PvP sets as possible.

And then run battlegrounds a lot.
This is the practice ground, where you learn your set up, tweak your macros, etc.
Plus you earn honor here, which gets you much better pvp gear.
You'll probably want at least the 2 minute trinket from honor before you do arena.

I've not done much 3's; in 2's so far I've played only a single toon.
But could see playing both (or all three, in 3's) as DPS working.

Losing constantly does suck.
But your personal MMR raises or falls with wins or losses.
If you queue at primetime on Tue (after patch) or Mon (before patch), or in the afternoon/evening on weekends, the pool of opposition will be huge, and you'll end up against opponents much closer to your MMR.
Keep at it, and you'll get your 8 wins.

It might be worthwhile to run a single toon at a time, with someone who is at least half geared.
To get your weapons, which will be 2-3 weeks of arena; weapons are a substantial boost.
It is hard to break in, mid season.