Summarize the following:
Lay a mat or old sheet down on the ground to protect the seat and bars from dirt and scuff marks if you've turned it upside down. Make sure you are in an open, well-ventilated area that can get wet without ruining anything. You don't want to blast any of the dirt away, you simply want to wet the bike and remove and loose dirt and grime before you start scrubbing. Never use a high-pressure hose or nozzle setting. This can force water into your components, causing internal rusting or de-lubricating important junctions. If you desire, you can also add a bike specific cleaner, but avoid using ordinary dish soap as it typically contains salt which can corrode parts of the bike, including the frame. You will want to use a different bucket and sponge than the ones used for your drivetrain. Grease from the chain and cassette will get on your frame if you don't use fresh supplies, ruining your clean-up job. You want to get into those as much as possible and you need to get on the inside of the frame with your sponge. The wheels make it difficult to clean the parts of the bike closest to the ground and tire, which are often the dirtiest areas. The tires, which will become dirty again the second they touch the road, do not need to be cleaned. But the metal rim of the wheel can pick up gunk that gets in the way of your breaks. Use the abrasive side of a sponge to clean off the edges and lightly wipe down each spoke so your bike looks clean and sparkly.   Use a toothbrush to scrub the hub-- the small cylinder in the center of the wheel -- and the nuts and bolts on either side of it. If you want to clean your tires, or you see large chunks of mud in the treads, use a big, heavy bristled brush (like the one sold with a dust pan) to clean them quickly and painlessly. The rear cassette is the collection of gears on the back of the bike. While you cleaned it briefly when you cleaned the drivetrain, you should take the time to make sure it is spotless when doing a full bike cleaning. Drip some soapy water into the cassette, then use a clean rag to "floss" in between each of the gears and remove any extra gunk built up deep in the cassette.

Summary:
Rest the bike in a stand, on a rack, against a tree, or upside down. Spray down the bike with a low-pressure hose. Fill up a bucket with warm water. Remove your wheels. Wipe down the rims of your wheels. Use a clean rag to get deep into your rear cassette.