I have spent quite a long time trying to perfect my recipe for great shaving soap, but even great soap can be disappointing if you're not using a good method for building shaving lather with your brush. The following is an illustrated example of one reliable method, though it's not by any means the only one. Since I didn't grow up shaving myself, I had to learn from somewhere. My thanks goes to the guys over at Badger and Blade for their suggestions and shaving "how to" resources.
Loading the Brush with Soap:
Fill sink with hot water and soak brush for 3-5 minutes. This allows the bristles to retain and control the amount of water in the lather.
Place a thin layer of water on your soap and let it soak for at least a couple of minutes.
Remove brush from the hot water and squeeze bristles vigorously, wringing out most of the water. Give it a couple of good shakes as well.
Dump the thin layer of water off of soap and begin swirling your brush in a circular motion with light to medium pressure. Add some plunger motions, using the whole brush and including the sides of the brush. Continue swirling until a paste-like consistency begins to form on the top of the soap and on the brush.
Bubbles mean too much water. A large volume of lather means too much water.
Continue to swirl until a noticeable audible and tactile difference is made when the brush moves over the soap. When the paste is forming the brush is noisier and seems to drag over the soap instead of smoothly going over the top.
Take a look at your brush, do the bristles clump together? If yes, you're done. If no, continue to swirl and load.
Now you can build lather on your face (see following), in your hand, or in a separate bowl.
Face Lathering Method:
Follow all of the preceding directions for loading up your brush with soap.
Give your face a liberal splash of warm water and leave it dripping.
Take the brush to your face and swirl/scrub/paint until the lather reaches a nice, thick consistency (peaks that stand).
If lather is too thick, add water to the brush a few drops at a time by dipping only the tip of the brush into your hot water. If lather is too thin, return to the soap for 5-10 second intervals. If you need more lather at any time during the shave just work the soap with your brush again.