Today we’re going to do Part One of How I Illustrate! This process is spontaneous, fun, and colorful. You can try it at home!
Step 1: Inspiration. For this piece, my source material/idea is this image from RedditGetsDrawn. There’s something fascinating about the fact that the author calls this “my very cute boyfriend and our plants.” In any other context, this image looks like a screen grab from a horror movie.

Step 2: Line art. I draw hella-simple line art. It can be smudgy or messy. This is where the composition is figured out. I moved the face to the other window to balance it out. I made the pots fun. I added in curtains.
Step 3: Basic colors. I locked the line art screen and set it to “multiply.” Then I added in shapes underneath. I used the Pen tool, but you could use the manual lasso or polygonal lasso and dump colors in places. When adding in colors, I make everything basically mid-toned.
Because I can’t quite see what I’m doing, the lines aren’t precisely matching up down there. I do not, under any circumstances, remove the line art screen at this point. Because I will begin to fuss. You’ll see what I mean in a minute.

Step 4: Highlights/shadows. I take the polygonal lasso tool, make a fresh layer, and start adding in highlights using a textured brush. Then I make another fresh layer and start adding in shadows using a textured brush.
Step 4 detail: Here’s how the highlight and shadow layers look on their own.

Step 5: The Reveal: Completely delete the line layer. It is not coming back. (Bye, Felicia.) You’ll be left with something sort of funky. Stuff won’t line up. Nothing will be straight. You will notice your mistakes. You will despair. Too late.
Step 6: Levels and touches. Here’s the part where you add in some contrast and add in a few details to the spots that look weird. (I realized, for example, that the curtains didn’t have any shading.)
Click here for the final steps: adding in some line work, highlights, definition, and color adjustments.