After being in the Weapons Department of a submarine crew, I generally swear by checklists, or a tthe very least, not just a 'let's think about this' session but as close to a walkthrough as I can manage. Vacation planning? Major holiday shopping/preps? New pet? (Other unusual circumstance?)

Imagine what it will be like to live through the time and actions that you expect, and almost guaranteed, the gotchas will pop out like a sore thumb, and you'll be planning ahead for those.

Wherever I can get to a checklist level, though, I do. Even if it's a list of possible options that I only select a few priorities from each day, it keeps me in mind of the possibilities and things I may be neglecting, etc.