Wear good trail running shoes or boots and center your load.
Wear good socks and use Bodyglide Anti-Chafe Balm on your feet.
Fully hydrate before and during your march. Don’t run.
Load your pack with 30 lbs of weight and hike for 1 hour or more.
If you need to carry less – then do so. If you want to carry more that is fine as long as you have legs that are well conditioned.