Breaking a zone is simple, but it requires everyone on the team to be on the same page.
First, DON"T try to take on the zone via isolation. Most plays that fail against a zone fail when individuals try to take it on.
First rule: ALWAYS have someone at the top of the key. This person's role is very simple they recieve the ball from the wing, then either reverse it to the other side, dump it inside, or take the shot if they are open. If the play breaks down, they are the first player back on D.
Rule 2: Have shooters on both wings.
Rule 3: The big men must be prepared to pass the ball back out to the wing when they get it down low. The big men should work together to screen eachother to allow the other to receive a pass from either the point (top of the key) or from the wing).
In addition, one of the bigs can flare out to set a screen for the shooter on the far side while the ball is on the other. This way, when the ball is swung around, the wing player will be open.
If you see a zone defense spreading out, then it's really just a bad man to man and you should attack it through driving to the hole and drawing fouls off the big man.
Rule 4; If the zone is loose, DRIVE. If you drive, the bigs should move to the baseline for short jump shots if you decide to dump the ball off. Or draw the foul on the big man, or kick out to open shooters if the zone collapses.
Don't put your head down. You need to see where everyone is.
IMPORTANT: A zone defense if run properly will move to the side of the court that the ball is on, which is why you should start from the side. Swinging the ball from one side of the court to the other will create open shooters and open up the inside for the big guys. Zone is designed to shut down one on one players, and to shut down teams that cannot shoot well from outside.
if your team can't organize this, then at least make sure you all play good defense and get back on D.