Although finding food is the least important essential survival component, it is still important to stay nourished and energized. Remember you can survive weeks without food, but the elements and lack of water can kill you in a few short days. However here are a few simple tips to help catch some fish if you are near a water source.
Absentee Fishing - If you are prepared enough to have fishing line and hooks then this will likely be your most efficient means of catching fish, and probably be your best source of food. One way to set up a series of fishing lines (the more lines out, the better your chance of a catch) is to tie a rope or line across the width of a body of water. Then bait a few hooks and attache to lines long enough to hang in the water from the rope across the water. Tie the lines to the cross rope in intervals of a few feet and make sure the baited hooks are not sinking too deep. Check back every so often (could be a few hours) and see if you have a catch!
Fish Fences and Corralling - This method is a bit more tedious but is for those who are not prepared with fishing line and hooks. The idea is to build a fence out of sticks and twigs or any kind of rope or line you have available. You want make sure the fence is strong enough and tight enough not to allow larger fish to pass through. Set the fence up in the water in a way to funnel the fish into a narrow section of water and after a while slowly close the fenced in area smaller and smaller till you have a higher concentration of fish. Once trapped, you can spear, net, snag, or grab the fish in the smaller area.