As a guideline, what is the biggest general concern to be wary of in revising 501(c)(3) bylaws?
Since bylaws are often ignored until there is a fight within the organization, the most important thing in my opinion is to avoid ambiguity. Be sure that you say what you mean and mean what you say. Avoid the passive tense and assign responsibility where you want some person or group to be responsible to see that something happens. Be sure that the bylaws reflect the constituencies necessary for the effective functioning of the organization. I think probably the most important provision in the bylaws is the provision allowing the removal of directors if a majority of the board believes it is important to do so. It provides a great deal of leverage if you have to deal with unproductive or obstructionist directors.
For a lengthy list of specific concerns, see Ready Reference Page: “Bylaws Function as 'Constitution' of Nonprofit Corporations.”
Want to know more about preparing bylaws? Consider purchasing our pre-recorded webinar Bylaws: The "Constitution" of Nonprofits - The Art and Science of Making Them Work.