Food is how you get more stamina. Meats give more health than stamina, while fruits/veggies give more stamina than health.

there are little colored forks on each food icon, red for health heavy, silver for 50/50 health/stam, and gold is stamina heavy.. i usually eat one stamina heavy food and two health. Also remember you need to be full rested or stamina will regen very slowly, especially when wet

The other thing is if you are wet, cold or aren't rested, your stamina regeneration will be impacted. Always make sure you have your rested buff when out and about.
Early game, honey is a great, sustainable and easy to get food for boosting your stamina.

You need to find honey, it's so stupidly important it's not even funny.
Check every wood structure in meadows that's alone for a nest.

If you have the tech to build a fermenter you can build one and make stamina meads. If you have killed the first boss and hung its trophy up on the stones you can use its forsaken power. While its active it reduces the stamina cost of any action you take.

Originally posted by knighttemplar1960:

If you have killed the first boss and hung its trophy up on the stones you can use its forsaken power. While its active it reduces the stamina cost of any action you take.

Eikthyr's power reduces stamina cost of running and jumping by 60%; not all actions.