To add to that suggestion, there is also a relatively old, but still applicable tutorial written by Tarn, which is of the same premise. This lighting enhancement
tutorial walks you through the process of using grading to artificially add light to a composite/effect; in this instance, the method is used to enhance a "lightsaber clash".
While the tutorial is created with Chromanator in mind, the principle still applies, and the method can quite easily be adapted to the current programs. Be sure to grade the footage first, and then complete the roto-scoping of your effect, to prevent the grading from having an affect on the light saber(s). If you have any questions about this, feel free to ask.
You may also want to consider utilizing real light sources for this type or work, as an alternative to the grading avenue. For more complex shots, using an actual light source, as apposed to trying to artificially create light interacting with the environment, may be more time effective.
Both methods have the potential to look quite realistic, it simply depends on the amount of care and attention to detail put into the effect. Perhaps a combination of both, real light sources, and grading, is something to be looked into as well.
In regards to your signature; while I find it rather creative, it is also quite large. I suggest making the dimensions considerably smaller, as large signatures can slow down the entire page for those with slower internet connects, as well as simply being distracting, and taking up an unreasonable amount of space.
Currently, your signature is 800x477. Although not a standard to which you must abide by, a recommended size for a signature is 400x110. This is a fairly reasonable size for a signature, and is more than acceptable.
I have taken the liberty of resizing your signature, to give an example of what it would look like at a more appropriate size. I have only slightly cropped some areas of the image, and then resized it to 400x207, which should be suitable. Re-sized signature
I will not remove the signature from your post, but advise that you change it at your earliest convenience. You do not have to use my alternative, but as it stands, it should still be re-sized.