I keep my digital setup as simple as possible and use a single painting program plus two auxiliary programs.
Clip Studio Paint
This is a fully equipped illustrator’s studio in digital form.
The software makes painting, drawing, and coloring genuine pleasures.
The brushes respond beautifully to the touch, and the brush engine is powerful. In fact, it adds what seems like a million potential tweaks to every brush. And that enables me to customize existing brushes to my exact needs. Or even create unique brushes from scratch.
Changing brushes, and changing brush size and opacity on the fly, are a breeze.
Selecting colors, or selecting variations of a particular color (hue, value, or blends), is simple and very visual.
One can also work on either raster or vector layers, using multiple combinations of the two in a single illustration.
Also integral to the program is a book layout function. While designed mainly for those making comics, I use it to create picture book layouts and book dummies.
Link to software: Clip Studio Paint
Lazy Nezumi Pro
A strange name for an extraordinary piece of software. While its primary use is as a steroid powered brush stabilizer, it also comes with an impressive collection of drawing guides. The one I use the most is the perspective ruler.
Although Clip Studio Paint has a built-in perspective ruler, I find the Lazy Nezumi Pro version provides more flexibility and power.
Link to software: Lazy Nezumi Pro
This small program overlays the digital canvas with adjustable grids.
These grids are variations on the classic Golden Ratio proportions and are most helpful when in the construction and layout phases.
Link to software: PhiMatrix