So I reached the top of the ladder and broke 2000 points (I've been playing the last few days as Boof Boof Boof.)
But I don't care if there's any reward or not honestly, since using the success I had as a teaching tool for others is enough of a reward ^_^. I decided I'd give a few tips to people looking to do well here, since I see a lot of dedication to the game in those I face, but very little knowledge of its mechanics.
This is sheer opinion, obviously, and I don't want to start an argument really, but doubles is a ton more strategic than singles. It focuses on a lot more elements than singles, and after playing a bit of both over the past year, I definitely believe this requires you to understand the workings of the game, damage rolls, mechanics, strategies, and everything far and wide. Many people are using 252/252 spreads, since that's common in singles; you have to do more calculations and take into account more when creating spreads in doubles, since Pokemon of BOTH attack types will be hitting you.
Second, and for most established singles players I cannot stress this enough, STRONGLY CONSIDER WHAT YOUR OPPONENT IS LIKELY DOING WHEN MAKING A MOVE.
I have seen SO many straight 6-mon Trick Room, Sun, Rain, etc. teams that focus on THEIR STRATEGY and have zero concern for what the opponent could do to stop it (these teams don't work against seasoned players...almost ever.) Even if these players do look at what the opponent does, they still focus way too much on executing the strategy rather than making a good play. Put yourself in the opponent's shoes. If you were them, what would you do? Which Pokemon would be attacking which? Which Pokemon of yours are threatened? By spectating battles between high-rated players and observing their moves, and by simply playing them, you can understand why they're making specific moves. You're never above anyone else; always strive to get better. There's always something you can improve on at this game.
I recommend looking around for battle videos of experienced players, try to see what they're doing as far as team composition goes, and how they play. I also recommend not copying their team EXACTLY, but make sure you look at the concept and keep that consistent. For example, if there's a Cresselia/Metagross combination you like that utilizes Trick Room and Swagger/Lum Berry, but you don't like how Trick Room is used, try Thundurus with Swagger and Garchomp/Metagross instead. Just remember, as I mentioned in the tip above...you can't just think "IF I GET SWAGGER OFF, I WIN!" Your opponent may Rage Powder your Swagger with their Amoonguss and Heat Wave, effectively ending your attempt. Always take into account all possible threats. If someone shuts down your team and you failed to identify the threat or could not handle it, analyze it rationally (don't simply say "it was a gimmick, BS!!) and mold a Pokemon or a moveslot to better deal with that threat.
So in essence, look around for established doubles/VGC players, practice on PS/GBU, and remember the game is NOT about executing your strategy, but how well you are able to deal withyour opponent's team/moves/strategy.
Good luck to anyone out there giving this format a shot; keep an open mind, a winning mentality, and an attitude that promotes learning and improving!