ALWAYS take a deposit and ALWAYS require a credit card be on file. You also need to have in your contracts that if they don't pay after a certain amount of time you will charge the credit card on file. This needs to be on the quote that they sign. This is a non negotiable. Nothing gives me less energy than chasing down someone for a few hundred dollars.
For bigger jobs, arrange the time that you are going to do the final walk through and take payment. Before that, make sure to schedule your time to do your prefinal walkthrough where you can get your punch list.
