Sketch examples with people (or pets) by Dan Dwyer. I started digital sketches with Sketchbook on a Cintiq display, but most recent sketches are on an iPad Pro with Procreate and sometimes Sketchbook, UI is very similar. I have also tried Fresco and Concepts… I still like quick sketching and markers on paper with other designers for brainstorming ideas and forms…

Hand sketches help to show functionality…

I like the style below, because it is quicker, easier to make sketches consistent, and easier to highlight detail or functionality choice-points…

…and here are a few Birthday Card sketches. Sometimes I do these on iPad and sometimes with marker and colored pencils.