Painters tape is your friend❤️

Use tape to get straight lines!! This is how I get all my court lines in my tennis paintings and any straight edge I need!

Tips:

Be mindful of watering down your paint too much, if your paint is too wet/runny it will seep Below the tape line.

Also, I remove the tape right after, when the paint is still wet, to avoid a weird edge.

Clean up any jagged edges or blurred edges with extra paint and a fine brush after the initial paint line you made with tape has dried (I have tried to fix or wipe paint wet and it usually doesn’t work).