3M Post-it Arrow Flags

3M Post-it Arrow Flags

I use these to mark cues in my prompt book. They are easy to see in the booth, easy to change, and easy to distinguish between different types of cues. The arrow points also can point specifically to the cue line (they are transparent-ish so you can see through them pretty good too.) If you're worried they will fall off (which mine never have) you can put your pages in plastic sleeves.