Evenly sauteing green beans
Try blanching them first, that way they will be almost cooked before you start frying them. Just drop them in copious boiling, salted water, allow the water come back to a boil (over high heat, it shouldn't take more than 30 seconds or so, covering the pan will quicken the return to a boil), then allow them to boil until they are the brightest possible green (that can take anywhere from a few seconds to a minute). Drain them like pasta and then plunge them in ice water to stop the cooking. Drain the ice water after the beans are cold.

You can do this part hours in advance if you like, that would make the final fry at meal time go super quick and easy. They will be evenly and perfectly done by just thoroughly heating through when you fry.