Stick-on heel grippers should be available in any shoe store, if that's where your problem area is.
Tongue pads are harder to find - they're available for online ordering, or if you have a swimsuit with bra pads that you don't use, those work perfectly under the tongues of my running shoes.
Depending on how your shoes fasten, you may be able to set up the ratchet to close tighter on your smaller foot.
"I felt [the women's Olympic marathon] was as important as women having the right to vote, because talent, strength, and capability cannot be fully realized if there are no personal rights to allow them to be visible or be deemed significant in the first place." - Kathrine Switzer, Marathon Woman