Proper storyboarding begins by understanding the various glyph creation strategies, deciding which one would be best for every concept that still lacks an image and would receive your contribution.
Then, thinking what to put in the image. And whether it needs an animated image as well, to help conveying the meaning (but keep in mind that the static version is the one that will be seen more often, hence it should be informative and understandable enough). What elements should be in the glyph? Also keep in mind that a glyph cannot be overcrowded, but also needs enough information to convey the correct meaning.

An example:

• Noticing (from the Dictionaries or from the sentences and tutorials) that "day" and "night" are both without picture
• Noticing that they are opposite and complementary concepts
• Deciding hence for the "opposition of concepts" stragegy (also called "Bongard approach")
• Writing a description that could go like:
  The same scene (for example a landscape with a lake and trees) can be drawn in the two different moments of daylight and darkness, with sun and moon+stars, in two halves of the glyph. Then highlighting alternatively one of the two scenes, the concepts of "daytime" and "nighttime" could be conveyed.
• Submitting this description with the automated story boarding system [temporarily disabled] or emailing it to the authors.
  
  The story boarding system is very easy to use/access: from the explanation page (e.g. this) of any core vocabulary glyph (not a composite, noun or phrase) you'll find a link like "Describe" or "Comment". Clicking on it will access the system and a description for the glyph can be there typed and automatically attached.

  On a side note, an "opposition of concepts" strategy is to be preferred in this case: while probably a night landscape (or even a black glyph with some stars and a moon) would convey the meaning of "night", a daylight landscape on its own would very probably present many alternative explanations, and hence fail to unambiguously convey the idea of "daytime".

The suggestion of glyphsets (2 or more glyphs made out of the same strategy) is particularly appreciated, since it enables more than one glyph to be created with small modifications of a template. You could paste the same description referring to a possible glyphset in all the glyphs to which it could be applied, or you could just email it.