Both of these postcards, made in September 2020, have acrylic paint scraped across them to create textures or visual interest. What I do is take a plastic scraper (the kind you would buy to use in spackling – they often come in sets of three, in different sizes), put a blob of paint on the art, and scrape across the image.
In this way a layer of paint is laid down. You can make it as thick or thin as you like. I often use a knitting needle or the end of my paintbrush to scribble lines in it.
You can also use the technique as a printing method. Scrape out the paint, scratch or scribble or whatever in it, and then press it to another artwork. The design will be transferred.
As another idea, a scraped-paint background can be made very quickly and then you can draw, collage, or paint on top of it.
Go on, give it a try!