Start with a broom, and end with a needle.
It’s an exaggerated way of saying start with big brushes then end with a small one, it’s a way of choosing brushes that can really help you when starting painting because it stops you focusing on the ‘interesting detail’ too early on.
Using large brushes to lay down bold and decisive strokes, helps to alleviate self-inflicted pressure to make the painting look finished too early on, in reality this never happens it’s like trying to re-landscape your garden without digging up the soil, you have to make the mess first to finish with the flowers.
How big is big?
If you use large brushes to start with it will teach you brush skills and the huge variety of marks that can be achieved with one brush rather than relying on another specialist brush to fix the problem.
For an example canvas 30x 40cm I would use a brush 2-4 cm wide.
What type of brush should I use?
One of the biggest stumbling blocks is indecision, if you only have one brush and two colours you’ve got no option, you just have to start.
I love filbert brushes, they are so flexible to use the hairs are quite long, arranged as a flat head and tapered to a rounded tip. For more details see: A quick way to understand brushes.
It’s always better to start with fewer brushes than to amass a whole draw and not start at all.