One of my most successful reality check methods involved carrying around
one of those tiny key ring torches during the day I would switch it on and off
a couple of time, I would do this several times throughout the day.

During a dream the torch would either fail to work totally or the light would
only be an orange glow. and on one or two occassions sparks came out of
the front of the torch.

Hope this info is usefull.