Learn the skills necessary to identify edible plants.
Many plants that can be found outside of most homes are edible. A short list of some of these in addition to familiar fruits and berries: beechnuts, burdock leaf stalks (peeled), cattail young shoots, immature flowers and pollen, dandelions, the young green leaves, tubers and flowers of daylilies, elderberry flower and fruit, foxtail grains, the stems, leaves and flowers of fireweed, juniper/cedar twigs and berries,oak and pine seeds, reindeer moss, rock tripe, waterlilly, thistle stalks and roots and wild rose.
If you have these plants around your home or find them while in the forest, many of these are best if boiled which takes away much of the bitter flavoring.