To make big shoes fit smaller, there are several effective methods to try depending on the shoe type and how much adjustment you need:

1. Wear thicker or double socks to add volume to your feet and fill the extra space inside the shoes, which works well for slight size differences.
2. Use insoles or add an additional insole on top of the existing one to reduce interior space and provide cushioning.
3. Insert tissue paper, cotton wool, or specialized toe fillers in the front of the shoe to prevent your feet from sliding forward.
4. Use heel grips or heel strips inside the shoe’s heel area to stop your feet from slipping and to tighten the fit.
5. For leather or suede shoes, dampen them lightly with water and wear them while they dry so the material shrinks and molds to your feet.
6. Apply tongue pads to make shoes narrower and more snug.
7. If the shoes have laces, try tightening them using techniques like the runner’s loop to lock the foot in place.
8. Consider visiting a professional cobbler who can tailor the shoes to fit more perfectly by adding padding or altering the shape inside.

Combining some of these methods can enhance the fit, but if the shoes are excessively large, it might be better to get a smaller size for comfort and foot health.

These solutions are quick, affordable, and effective for making big shoes feel smaller and more comfortable.