The most common mistake is skipping or rushing the feasibility study and announcing a goal that hasn't been tested against real prospect capacity, which either leaves money on the table or sets the organization up to publicly fall short.
A close second is going public too early, before the quiet phase has secured the majority of the goal, which removes the momentum a strong public announcement is supposed to create.
A third is treating the public/community phase as an afterthought, handed to a generic calling vendor instead of run as a real campaign discipline, which is exactly the gap Catapult's Campaign Connect program was built to close: trained Engagement Officers, personalized ask amounts from prospect research, and a program run with the same rigor as the quiet phase.
Fourth: recruiting a Campaign Committee for prestige rather than willingness to give and ask, which quietly stalls solicitations for months.