Doodling in the round is a great way to derive the satisfaction of making art even if you don't think you have talent. It's totally non-judgmental, you just take a writing tool in hand and fill in the circles printed on the journal's page. Start with a pencil with an eraser to make changes, before working with ball-point pen or fine-line markers. Your confidence will build and soon, you'll be working in ink with no fear of mistakes. If you make a bad line just leave it and put down the one you wanted. If you color the piece extra lines become subdued and hardly visible. If you leave it uncolored, the extra lines become ornamental and add a quirky qualtiy.
Another approach is to work directly in colored pencils, markers, even water soluble colored pencils, ones that you can sharpen to keep a point since this work requires accuracy of line. Wait a while to use softer media like pastels, cray-pas or watercolor with a fine brush. Warning: Don't soak your paper and don't work in permanent marker as it will bleed through and ruin what's under it.
Also, lose the little critic on your shoulder. The one whispering negative things to stifle your creativity. Tell him to take a hike. If you show your work to others let both good and bad comments roll right off. You have to start someplace and you'll never grow without making mistakes. If you quit, you won't grow and you'll miss all the fun of creating artwork.
For another doodle/drawing idea using the circle format, look at bobbin-olive Productions, Important Dates, subtitled: Cat Mandala. Pick any theme and have fun doing it in a round format.
I want to try that! Great tips.