Finally a subject I know a lot about!

This probably depends a lot on if you tend to have foot odor of a regular nature or if it can get extreme. Not looking to lay out TMI, but my feet sweat a lot more than most peoples. Most of my friends who I backpack with have little problem and take no extra steps to control odor while I stop at least once during the day to change one pair of wool socks for a dry pair. They all appreciate it a lot, as they remember things before I discovered wool and stopped using traditional boots and went to light breathable shoes.

On a tour, I usually use wool socks with sandals, either Chacos on flats or cleated SPD sandals, even in winter. Lucky for me my feet don't get cold easily, so it works down to freezing temps with a high quality thick sock. Summer its either thinner socks or bare. I don't care if it looks dorky or not.

On the few trips that I have worn shoes, the insoles should be taken out, laces loosened and the tongue pulled up as much as possible. They stay in the vestibule or if in a hammock hung from the strap. More worried about a dog running off with them than having to shake out a spider in the morning. I punch a little hole in the toe of the insole and run a lace through them so they can air out without getting lost.

If its rained all day and is to humid to really dry them out overnight, then the newspaper trick is about as good as it can get. Shoe covers just make my shoes soak with sweat more, so I stopped trying to use them.

It also helps to really keep the feet maintained and clean. Not everyone needs a pumice stone, but if I keep my feet fairly callus free it helps a lot. I also have a foot maintainance cream that works really well, and a film canister(showing my age there!)filled with it lasts a long time. Way more than you wanted to know probably.