As with many things, the more that you do of it, the more blaze you get. The net result of this with photography is that you might go out on a shoot and forget something really basic, such as charged batteries, spare memory cards, your filters or even your lens cleaning kit.
A few things that I now do the night before (if I remember!) are to take a quick shot of anything just to make sure that all seems well. You might also like to make this a shot against a dark or grey background so that you can more easily tell if the sensor needs cleaning. By the way, I now set the camera to clean the sensor each time I switch off and this seems to help.
Then pack the bag in a methodical way and you’re ready to go.