D&D Turn Markers for attachment to a DM Screen

I recommend painting the numbers with a strongly contrasting paint. I recommend printing these such that the numbers are upside down. For more markers, paint in another color of paint (PCs vs Monsters) on the opposite side of the part instead. Each person in your party should receive a number that they keep over all of your sessions, and number your monsters dynamically per combat. Then again, know that this advice comes from a uni student, so you may try other ways as you see fit.