Probably goes without saying, but I make it a point to always tighten everything as if I were going for a ride, even when I might not. What I mean is, sometimes I'll take my bike out the car and think I'll just loosely tighten the QR, knowing it's just gonna come off next time I load it in the car. But, I've gotten in the habit of making sure it's really tight, just in case I change my mind and ride straight out from the house. Keeps me honest, you know?
Edit: I do this with other things. I had put on a new seatpost, but was just checking for fit and didn't have time to adjust it to the right length. I didn't want to tighten it until I knew how high I wanted it. I made sure I left it so obviously out of alignment (completely sideways) so I wouldn't forget that it wasn't tight before I took it out for a spin.
For 3 days, I get to part of a thousand other journeys.