2 tips I know of. One is that candle light has a high fall off, so a light, perhaps a point light...with falloff/decay set to quadratic can be a good start for the actual light.
The second is using volume lights to create the sss effect near the top of the candle wax. If you adjust the intensity curves of the light you can create different gradations of fall off from that 'light' too.
Also, using geometry for the candle flame, with ramp textures, can help simulate the varying colours and intensities throughout the flame...
Last edited by ben hobden; 18-07-2011 at 11:16 AM.