Churches are given wide autonomy by the U.S. Supreme Court and by the Constitution. Because they are given such latitude, there's certain things they should be in every set of by-laws. On no two churches are alike, there are certain things that are inherently important for it to be in every set of by-laws. One is membership, because members of the church enjoy certain freedoms, there must be some identification processes to have someone becomes a member.
Concomitantly, there must be some identification as to how a member can be disciplined or how they can have their membership revoked. Third, how their membership can be rescinded. For instance, if someone chooses not to be a member of a church as well. The by-laws should also clearly indicate within the body of the by- laws who is the final decision-maker in the church based upon the authority of scripture. This could be a Board of Elders, Deacons, or the Pastor, or an affiliation with the congregation otherwise.
The church had also set out in this by-laws the requirements for those dealing with youth and minors in setting out terms of how individual employees, staff or volunteers are going to be vetted, if you will, and how they're going to be checked out and what their guidelines are for their operations. Finally, every church set of by-laws should include its statement and its belief about marriage.