Washing a bike is a messy job. Begin by changing to clothes that fit the job, and putting on an apron. Next, find a work area that is appropriate. Gather together all the materials for cleaning.
Start with fill the buckets with hot water. Just like when washing dishes, warm water cleans better. Use a biodegradable dishwashing liquid or similar soap, and mix it in one of the buckets. If the bike is to be clamped, scrub inside the jaws holding the bike. Also wash area you will be clamping. The jaws will not scratch, but if there is dirt between the jaw and the paint, it may mar the finish.
If practical, remove the wheels from the frame. This will facilitate a more efficient cleaning of both the wheels and the frame. Install a dummy hub to allow for easy chain cleaning. Begin by cleaning the dirtiest items first, which is typically the chain and drive-train. Use a chain cleaner, gear brush and solvent which are made specially for this type of job. After scrubbing the chain with the chain cleaner, empty the chain cleaner and fill it with soapy water. Using two different types of solvents, a degreaser and a soap, is very effective at cleaning the chain and removing grit.