After grinding up to 900, hitting my qualifier, and then dropping back down to 650-ish in a single day... Here are my suggestions based on what I was able to do to improve myself as a player and my odds in the arena (almost back to where I was at before the weekend, haha):

1) If you're going for a real grind, don't try to do it during the weekend. This is when new PvPers are going to be playing, and it will be a very mixed bag of participants. Unless you are Gold or higher, you can and will get matched with unranked people. (It's +/- two ranks, so even Gold players will get mixed with Bronze players, and you can't derank from Bronze... so being Bronze doesn't really mean much except that you've won 8-ish games in ranked.) Playing during the weekend, I think, increases RNG of your teammates and opponents. If you do decide to try to grind out your rank during the weekend, stop doing it if you are hitting a losing streak. I made the mistake of continuing to play, getting matched with or against the same people, and having a lot of trouble.

2) Actually put time and thought into your PvP gear. I'm still not 100% sure on the stat caps or even the accuracy requirements, but you can figure out what you need by checking out the gear of the top ranked people on your datacenter (there seems to be a magic number for acc, but I'm not going to give that away :P). Mix your PvP sets with your prioritized stats, while ensuring that you still have the accuracy you need. For most DPS classes, this would be crit/det. Just look at the highest ranked players and you'll see what I mean.

3) Take the time to remind people of seemingly simple things at the start of the fight... such as the importance of securing the adrenaline boxes (so the other team doesn't land a clutch LB) AND the timing of all boxes. Just because someone has reached Bronze or even Silver doesn't mean they know about all these little small tricks. You'd be surprised how many games I've lost at the end because the other team was able to secure the adrenaline boxes.

4) Spend time learning a little bit about each job so you know when people can burst and when they can't. If you're not coordinated with your DPS partner on your burst, and the healer on the other team is pretty good, it will be really hard to down someone unless they actually mess up their positioning and LoS the healer. As a summoner, I generally tell people... "Remember, if I have aetherflow stacks, I have burst." It's always better to be coordinated in your kills. Raw numbers mean nothing if they aren't effective.

5) Make mental notes of the strengths and weaknesses of both your teammates and enemies. For example, I know a really high ranked healer on my datacenter who is one of the best healers I've seen, but they tend to LoS their teammates way more than other healers... so I know if I am against them to just force them to pillar, bind them there, then burst their teammate down (if I can). Also make a note of who does or doesn't follow marks (so you know to just follow their lead if they refuse). Yeah, it's bad sportsmanship for them to ignore marks, but if you HAVE to play with them... might as well be coordinated, right? There are some high ranked people on my datacenter who outright ignore marks, and they got to that rank somehow, right? They must be doing something right.

As far as the rest of the stuff... that's just good gameplay, but those are my five suggestions for improving your game odds. It's frustrating when you get teammates who can't or won't listen, so if you are employing all of the above suggestions and still losing... take a break, blow off some steam, maybe queue 8v8 for a while... and try to queue another time.