Pep Guardiola once explained that he trained his players so that they would achieve peak performance twice per year: once in late November, then again in April. He has a month to get to his first benchmark and it is clear that his players have some work to do.
In the article Pep referred to players peaking in terms of physical fitness. He did not attempt to argue that team unity or cohesiveness and understanding would peak around the same time.
As Barca (and presumably other teams aiming for the same objective) reach this first physical fitness peak they must also reach a state of mental/psychological peace. To do so, players must either A) figure out how to best work with what they have (their own skills and those of their teammates) or B) push to improve the way they work and the way those around them work so that the team can work well together. The Rub: In the delicate world of superstar athlete egos, achieving that sort of harmony requires so much self sacrifice it is nearly impossible to obtain.
If anyone can do it, however, it is this Barcelona team.
A great indicator of this is Barca's team leadership. Messi, Xavi, Iniesta and, increasingly, Abidal, have been poster children for self sacrifice. Never egoistic in interviews, they, along with Pep, set the tone for stability, humility and squad cohesiveness in games. Now if only they can bring both physicality and such unity to peak.