Seems to be some traffic recently regarding brush painting Acrylics etc. Came across the Link below which leads to a PDF file which can be saved to your computer if you want, and which gives some useful tips.
http://www.ipmshpm.org/EBooks/brush-paint-ebook-rev1-1.pdf
http://www.ipmshpm.org/EBooks/brush-paint-ebook-rev1-1.pdf