Examine the script for the show and what the lighting requirements are. For each scene, the lights may need to change position, intensity and color. Draw out a lighting map for each scene with notations of color and how bright you need the light to be. Detail what possible supports you may need and what paths the actors will take.
Plot the number of LED flashlights that you will need for each light source. A bundle of six lights can recreate the sun or a searchlight, while a small bundle of three can replicate a fire. Stars get one LED flashlight each. Also plot what colors you need. Mix shades of colors to give an organic feel to light. For example, fire would be orange, red and yellow.
Zip-tie the LED flashlights into place on the supports or props where possible. If zip ties are not possible, then duct-tape the LED flashlights into place. Replace the clear flashlight lens with colored lens for effects. Load fresh batteries into all the lights. Turn the lights on during practice rehearsals to make sure the lighting is correct. If not, then move the lights. Make sure to run through all the scenes. Turn the lights off when they are not being used to conserve battery power.
Buy extra flashlights for backup in case a light malfunctions or is broken during the show. If the light breaks during a scene, wait until the end to replace it. Stage hands should never be seen during the play.