Choosing the right brush size and shape can be a big decision when you are just starting out as a painter.
In my opinion, size does matter – especially if you are painting a big canvas, I recommend you start with a big brush.
The shape of the brush matters too – to understand what each brush can do and the marks they can make painting a sampler can really help you get familiar with what each brush can do.
Try them out and see what kinds of marks they can do.
Pulling the brush in different directions, or twisting the brush makes such a difference.
The more miles on the brush you do, the more you will understand what size and what shape will work best for what you are trying to achieve in your painting.
I suggest you try different brands if you can, and look for a brush that holds its shape after a few uses.
Really, anything goes!
My only “don’t” is don’t use watercolour brushes for acrylic. In my experience they just won’t hold their shape. And I often use brushes marked as ‘acrylic’ for watercolour – it’s my personal preference.
Get some miles on some brushes and you’re bound to find your personal preference too.