The simplest way is to think about the groups you are part of and schedule key moments where you will gather signatures into your calendar.
At church or in a faith community
At school, tafe, college or university
In a community group or in my neighbourhood
Consider whether you will have an opportunity to make a short presentation to explain the petition and ask for signatures and who do you need to ask in order to do this?
Are there other groups are you in contact with who you could invite to promote the petition (such as local businesses, community groups, and local events or festivals)? Consider when and how will you get in touch with these groups.