Alright, I think I'm starting to understand doubles a bit better...
*One has to be aware of everything going on in the screen and not get distracted by the opponents.
*It's better to combo off your teammate/help him at all times than it is to have two 1 v 1s.
*Most high placing doubles players do not have good teamwork(their singles skills carry them), but this is shown mainly at large regional/national events where teamwork is a must, and the best teams place top.
*Practicing w/ your teammate outside of tournaments/events helps even more for synergy, followups, and survival tactics.
*Teams w/ gimmicks such as healing(ZSS blaser, lucas/ness down-b), easy KO followups(ex. DDD dthrow --> Lucas Upsmash), strong stage control(Snake grenades, C4, etc., Wario's mobilty, MK's speed & tornado) are the best teams regardless of how strong certain players work together because even w/ good teamwork, gimmicks always have the advantage and are naturally better teams.