All of the top bjj competitors have at least one thing in common, which is a solid group of people to train with. Although bjj isn't considered a team sport due to the 1 on 1 nature of the matches, the training involved until that point relies heavily on the team.
So how does one go about being a good team mate?
I believe it comes down to supporting your team mates in any way possible, even if it is something as little as showing up to their matches.
In class, one good way to make sure the whole team is benefiting is variation in training partners, and adjusting your game plan to help out your training partner.
By this, I mean having an equal amount of "A" game training for tournaments, and also just drilling movements you are not comfortable with yet (but need to work on). Getting tapped in training especially by your team mates is a natural part of improvement, and without it, you can not get better!
now a highlight of one of the mendes brothers.