If you've got canvas shoes like Tom's slip-ons, you can water proof them quite easily with a beeswax bar. Simply coat the entire shoes with the wax, and then take a hair dryer and "melt" it in to the canvas. The coating should start to embed itself into the shoes. For best results, let it set overnight.
If you've ever washed your shoes and thrown them in the dryer, you'll know that they never come out the same shape again. This will preserve their form and allow you to dry at the same time.
By painting each button with a clear (transparent) nail polish, you can prevent the thread from fraying and unraveling.
Zipping the zippers helps ensure the teeth don't get caught on anything, and undoing the buttons ensures the buttons don't pull on the button holes. Delicate clothing can be placed in a laundry bag to protect them from other items.
Hang your clothes in your closet with the hangers reversed once a year. As you pull clothes out, reverse the hanger. Every year giveaway clothes you never took out (hangers facing in the original direction).
If you don't have any soap available, a tiny bit of lip balm or petroleum jelly can be used instead.
Let it sit overnight, and in the morning shake it all out. For maximum odor removal, leave the now treated shoes in the sun for the day. Repeat as necessary.