Observe the color of the beans. Most beans have distinct coloration. Beans generally come in green (lima beans, peas, green beans), yellow (garbanzo beans, mung beans), red (kidney beans, red beans), brown (pinto beans), and black (black beans). It's important to identify the beans ahead of time, because different beans need different conditions for growing and cooking.
Observe the shape. Most beans are kidney-shaped (kidney beans, lima beans), roughly round (garbanzo beans, peas), or roughly oblong (pinto beans, black beans).
Observe any markings on the beans. Lima beans, for example, have striations. Black-eyed peas are brown with black spots or "eyes."
Combine the data from your observations to identify the bean. Kidney beans are dark red and kidney-shaped, for instance, while lima beans are green, kidney-shaped, and have light green stripes.