Some process gifs as an overview of my general approach when it comes to painting. I have made other posts about my process before (which you can access through the #answers tag) but it does seem to be a popular thing to ask about, so here’s another one-size-fits-all kind of answer.
For environments I follow a very loose sketch and move right into blocking out main shapes and overall colour scheme. For things that may require more detail due to proximity (e.g. faces) I will do cleaner lines.
It can be fun to paint messily (see the maidenhair drawing) but in many cases you may want to adopt habits which will speed up your process such as locking down transparency (or use layer masks or both) for things which need it so you won’t be wasting time cleaning up edges later. Natural shapes are more forgiving of lines which are out of perspective; don’t be afraid to use things like polygonal lasso or shapes when drawing buildings. Use large brushes when building up colour scheme; the whole thing will read better without unplanned strokes everywhere.
Sometimes I get comments about detail. My paintings aren’t usually very detailed. I like to draw things from far away, and the further away something is the easier it is to draw. Shapes can be implied. There is no need to draw every petal of a flower or ever branch of a tree or every blade of grass. A few blades of grass can hint at a whole lawn.
For brushes I primarily like to use Photoshop’s default hard/soft circle brushes, occasionally flattened to an oval. The default chalk series is also good. I also often make custom brushes for paintings, especially for different types of foliage. When making or using brushes pay attention to brush settings like Scattering, Brush Tip Shape > Spacing, and Shape Dynamics > Angle Jitter. There is no magical brush which will solve all your painting problems. There are brushes which are better suited for some purposes than others (e.g. a general leaf shape with scattering and angle jitter). Learn how to fish.
After all your fundamentals are there the painting process is really just a matter of defining and rendering until you feel like it’s time to stop. This is the easiest part, although depending on how defined you want your painting to be it can also be the most time consuming.
That’s all for now. :)