HAVE YOU TRIED SGRAFFITO YET?
It is a little more adventurous than straightforward oil or acrylic painting. A little more fun, too, to see the effects you can achieve.
Choose your subject. Look at my gallery at the deep sea fish (Barbara Le Blanc). A series of small subjects mounted together make an effective picture.
Paint a bright, intense colour using acrylic paint on a waterproof support such as oil paper. Pastel colours don't show up properly.
Cover the whole page with a single colour oil pastelle. It makes a good medium for scraping off to reveal the underpainting where you want to.
Using a sharp instrument such as a scalpel or knife, scrape away as much of the oil pastelle as is required to create the shape of your subject, drawn freehand, into the pastelle. Use suitably directional strokes to suit you subject.
Make a series of similar topics and mount them on board, card or whatever you choose. Frame if you wish.
This method also suits larger single subjects if you prefer.
It is not terribly messy, but it is fun.