Once you've identified the most convenient low spot from which to enter and exit ... enter! The fellow in the photo is Michael Lamanna, director of instruction at The Academy at La Cantera in San Antonio, Texas. Notice that Michael is carrying the rake into the bunker with him. Contrary to what some golfers believe, it is not only within the rules to take a rake into the bunker with you, it is advisable to do so because it speeds up the process.
(Note: Be sure you do not allow the rake to touch the sand, except when you drop it before playing the shot. If you do anything with the rake - or your club - that can be construed as "testing the condition of the hazard," then you are in violation of the rules. For more on this, see our Rules FAQ, "Is it illegal to take a rake into a bunker?")