I posted this tip about 4 years ago (elsewhere) and I thought it would be time for a reprise.
Eventually it dawns on Painter users that there are in fact no brushes at all in Painter, just a bunch of parameters that are set. What appears to be a special brush is just a particular setting of the available parameters in Painter.
Once this is understood then the next thing is how to learn what all those controls for brushes do, in a systematic and ordered way. Some parameters are obvious, like "Size" for example; but others are more mysterious and it is difficult to tell what they do unless the conditions are right. Some controls work together as well as separately, like the "Well" controls for example.
So...I thought of an interesting and fun way of quickly learning most of the parameters.
Pick a brush, any brush and write down every single setting. Some settings are greyed out because they are not used by all the dab types. It might even help to draw up a sheet with all the parameters and blank spaces for the settings for future use.
Anyhoo...after noting down *all* the parameters, select a completely different brush and start changing the parameters one at a time until they are all the same as the first brush.
The "General" palette contains the major basic brush definitions.
This new brush is identical to the first brush you used. The key to understanding the parameters is to use the brush after every parameter change, and slowly watch it turn into the other brush. This way you can pin down the most dramatic changes to a particular parameter.
This is time consuming but really worthwhile in understanding how to make Painter do exactly what you want it to.
If you want a challenge you can ask someone to describe the qualities of a brush they would like and then try to make it. For example someone asked me to make them a brush that looked like tangled string when it was used slowly but as it was used faster the tangles straightened out.
Understanding the parameters well makes it easier to modify the standard default brushes, as most of the time they are fine as they are but occasionally you will want just a small specific change.