When spike marks and glow tape aren't enough, you can mark your quarter marks and wings with LEDs. There are commercial versions at decent prices. Or, if you have a soldering iron and a hot glue gun, you can make your own for just a couple bucks worth of parts.
This Instructable is designed for someone with no electronics experience beyond knowing which end of the soldering iron to hold.
In keeping with the newcomer-friendly nature of this Instructable, the following parts list can be found at any local Radio Shack.
Total parts cost? About $2.78 each.
It is fashionable in some circles to make fun of the "Rat Shack," but where else are you going to go at 7:30 on a weeknight to pick up that last essential part for a show opening that weekend? So give them some love.