Make your process easy
The painting process is always about inspiration. But it doesn’t need to be difficult or overwhelming. Try to find brushes that meet your requirements, create your own set and use them all the time. From my experience of painting portraits and characters, two or three brushes (Hard, Soft and texture) is all I need. I don’t have to constantly switch between a large set of tools and can paint vigorously and quickly as I like. Keep it simple. Spend more time improving your artistic skills than creating custom brushes.