For communities
The mechanics are in Manage RFPs. This page is about running the process well.
Write a scope you can score
Two or three bidders describing different work is not a bid, it is three estimates. State quantities, materials, access constraints, the schedule and what "done" means.
Publish a budget range
Counter-intuitive and usually right. A range filters out bidders you would never accept and stops serious ones pricing blind. Where your bylaws prevent it, say so in the description so nobody wastes a week.
Use required submissions
Insurance, licences, references, quotes and past work are checkboxes, not prose. A contractor who does not supply insurance because it was mentioned in paragraph four has cost you the whole bid cycle.
Set scoring criteria before you see a proposal
Criteria, weights and maximum scores, written before submissions arrive. A board that can show a weighted score across named criteria is in a completely different position from one that says it picked the bid it liked, particularly where an owner challenges the award.
Price should be one criterion, not the only one.
Answer questions publicly
If an answer changes how anyone prices, every bidder needs it. Publishing answers is what keeps the bid defensible.
Where the change is material, publish an addendum and consider extending the deadline. An addendum is part of the permanent record.
Pre-approved or open
Open bidding for straightforward work with clear specifications. Pre-approved for anything touching residents' homes, anything with specific insurance requirements, and anything where an open bid previously went badly. See approved vendors.
Assign more than one evaluator
Two or three evaluators scoring independently produces a better answer than one, and it removes the appearance of a single person choosing the winner.
After the award
Link the expense to the awarded proposal in financial reports. That is what connects the bid you accepted to the money you paid, and it is the pair an auditor asks for.