Here is a sample organizing petition (not a weight of law petition)
http://interblog.org/petitionorganize.docTo begin you need a committee of workers that will carry the petition, donate money and organize the campaign. I find carrying a petition right off the bat is a very good start. It will give initial volunteers something to feel a part of and begin your base of support. Given the fact that it will take many months before the real official petition with weight of law is ready for signatures, this time should not be wasted waiting for a petition. This will be the committee-building period. In a few months as you organize, this initial opinion petition will provide the infrastructure to qualify. Within a few months and 10-20 initial organizers you will have hundreds of names of folks that already know what you are up to, support the idea, and will help with funds and petitioning. These will be your constituents. Do not take these folks lightly respect them as you represent them.
Be advised that an individual willing to carry a petition is a rare bird indeed. Almost all are willing to sign a petition. Many, though not initially until you attain viability will donate funds. Quite a few will volunteer. But very few will actually approach the public with and circulate a petition. Protect that list at all cost. Kiss their buts until your puckered permanently. These folks are the core group that will determine ultimate success or failure.
Challenge your workers and the public with difficult but obtainable tasks. One I like that has proven helpful is setting a goal of twice the number of signatures required to qualify. Spew that challenge forthrightly at every opportunity. Historically NO, official petition containing twice the required petition signatures has failed to qualify. Additionally NO official petition with twice the number of required signatures has failed on Election Day. The idea is to approach the committee and the public from a position of overwhelming support and strength.