How often do you clean after off-roading?

Can someone give some general directions on how to clean the engine? I've never done it... I'm afraid of spraying water into something I'm not suppose to.... It's covered in mud.

 

cover electrical stuff and use a nylon brush for the major scrubbing, i don't like using a pressure hose, too much power and might affect something. I use a garden house with the shower nossle, some simple green or something and a brush. then use any trim polish of your choice.