One of the most useful things that an aspiring union organizer can do early in the process is contact the relevant national union and ask for guidance on how to decide whether an institution is pleading poverty or is really on the path to financial exigency. Relevant national union organizations include http://seiufacultyforward.org and https://www.aft.org/affiliate/06524 .
A couple afternoons spent with the publicly available financial reports, enrollment trends, and comparisons with similar institutions tends to be very illuminating with the national guide usually able to give good feedback on the near-term future of the institution.
Organizing is hard, unpaid work, so step 1 has to be establishing that, given the local constraints, a union will be making progress towards achieving goals instead of diverting resources from other important goals like keeping the doors open or becoming gainfully employed elsewhere with better working conditions.
What other tips do people have for those who are considering standing up a union to help get better academic working conditions?