You can catch fish with nothing but a hook, line, and bait; but you can present your bait better, and thus increase your chances of catching fish, it you use a weight and float. A weight will hold your bait down in the water, and a float will help regulate the depth at which your bait is suspended. Pictured below: Yucca fishing line rigged with gorge hook, stone weight, and stick float.
An effective weight can be made from a small rock. You can just tie the rock onto your line, or you can use another rock to abrade a groove around your weight rock. This way the string will stay more securely in place around the rock. Pictured below: Marble size rock with groove around it.
A float can be made of anything that will float and support the weight of your hook, line, weight, and bait. You can carve a float out of a seasoned stick. Pictured below: Float made of seasoned hickory.
You can also make a float out of a section of river cane or bamboo. To make a float out of bamboo just cut a short section of cane leaving an intact joint on each end. The air trapped in the cane will cause it to float nicely. Pictured below: Float made out of a small section of river cane.