Whether you're working with an IKEA standard (Image 1), a classic piece (2, 3), something fairly beat-up (4), or someone else's bad makeover (5), paint is a cheap and effective way to bring new life to furniture.
If you have a dresser or chair that you think could use a coat of red or blue, check out Sarah's tips for how to upgrade furniture with paint (and hardware). To add pattern, try consulting Lena Corwin's Printing By Hand; I had a good experience using it to stencil a filing cabinet à la Image 10. You can go freehand like Chroma Lab (Image 7), or consider following advice from this video to make a repeating pattern.
Images: 1. day-lab via Design*Sponge 2. Lonny 3. Country Living via Apartment Therapy 4. Little Green Notebook 5. Second Coat Design 6. Living Etc 7. Chroma Lab 8. Rebecka Oftedal for Design*Sponge 9. Kim Johnson via Houzz 10. Lena Corwin via Apartment Therapy