Summarize this article:

After rinsing your brushes, take a clean towel or paper towel and gently squeeze the extra water out of your brushes. Don’t wipe your brushes against the towel because this can cause the bristles to loosen and fall out. And never shake out the extra water, which can also loosen the bristles. After squeezing out the extra water, lay your brush over the edge of the table with the bristles facing downward. This will maintain the shape of the brush and prevent extra water from seeping into the head of the brush. Put a towel under the wet brushes.  Allow your brushes to dry completely overnight before you use them again. Never let your brushes dry while standing upright -- this can rust any metal parts of the handle and also loosen the glue in the head where the bristles meet the handle. Once your brushes are dry, gently fluff them out. Use your fingers to reshape your brushes if needed. You can also get the bristles slightly damp to reshape them. Hold your brushes in the steam from a garment steamer for a few seconds, then reshape the surface gently with your fingers. Try holding them in the steam from a tea kettle spout if you don’t have a garment steamer. Let the brush cool before you use it.

Summary:
Squeeze out extra water. Lay it flat. Reshape your brushes. Steam them into shape.