If you have to walk through the leaves, you cannot completely eliminate the sound. What you can do is walk slower, or mimic a different animal, so you don't have that two-legged, rythmic, crunch,crunch,crunch sound.

I have heard of people dragging a stick behind them to cover up the 'two-legged' cadence. I usually just walk slower and be carefull where I put my feet down.