Identify the source of the squeak
Dry the shoes completely
Remove the insoles and let them dry
Sprinkle talcum powder or cornstarch under the insoles
Apply a small amount of baby powder between rubbing parts
Rub a little petroleum jelly on noisy seams
Sand rough spots on the outsole lightly
Tighten loose parts with shoe glue
Replace worn insoles
Use leather conditioner on leather shoes
Check and tighten loose laces
Wear the shoes with thicker socks
Let wet shoes air-dry fully before wearing
Avoid walking on very smooth wet surfaces
Take the shoes to a cobbler if the squeak persists