Prepare. Wear dark clothing at nighttime and have a lot of weaponry readily available for any given task. Make sure your cloths don't restrict movement. Wear a mask and change your voice when talking. Don't leave any traces of who you might be. This includes fingerprints, shoeprints, or any kind of DNA. Move quickly. You have to be to escape any given situation before police or criminal back up appears.

As a general rule, I think those without superpowers who want to be a nighttime vigilantes for others need to behave more like ninjas than anything else. And never take on a job that you can't handle. Don't want you gettin killed buddy