There's a lot that goes into a collections policy, and Levelset has put out some great content on collection policies over the years. I'll touch on some key topics, while also weaving in some links to content I think will be helpful for you.
Essentially, a collection policy should create a few different plans of attack for recovering overdue payment. The different tactics for collecting payment may vary based on a number of different variables - like the type of project being completed, how comfortable you are with your customer and/or the owner, the payment terms on the job, the list goes on and on. And, those variables may influence which collection actions will be taken on which jobs. But, by putting a plan in place, it takes the stress and confusion out of making that individual collections decision - there's a guideline in place to follow.
Construction collection policy basics
With that being said, the backbone of a collection policy will be deciding which actions will be taken in attempt to recover payment and the timeframes those actions will be taken in. All of the other details in the policy will ultimately come down to what will be done to collect payment, and when that will be done.
For example - a construction collection policy should likely take mechanics lien requirements and deadlines into account. The policy should account for the timeframes associated with pursuing a mechanics lien, if necessary, that way the right to lien can be leveraged throughout the collection efforts. After all, failing to account for lien rights would take one tool off the table for collection efforts.
By drawing out all of the available recovery options - lien rights, legal claims, arbitration, sending debts to collections, etc. - the bones of a collections policy should quickly begin to form.