Imagine this is the opening sentence of a short story. The author uses the technique of mentioning significant parts or aspects of things and leaves the reader to work out the whole. Give glosses on what is left unsaid. Suggest a person and place.
"When the green light flashed, she put the green bit of wood with 8 on it on the hook and went in."
Glosses give the reader an idea of the significance of an item or a circumstance. In this sentence, "When the green light flashed, she put the green bit of wood with 8 on it on the hook and went in," there are various possibilities to consider. Does the author want the green light to be most important or is the number 8 somehow most relevant?
If this is science-fiction, the green light could mean the girl has arrived at her futuristic destination or perhaps gone back in time. The number 8 could signify how far forward or back she has gone - on a scale of 1 to 10 possibly. Had the wood been blue, maybe a blue light would have flashed. Hence the importance of using glosses as a technique. The reader is left curious but hopefully not completely confused.
Consider a gloss such as: Girl, alone, anxious but determined.
To add some personality, consider" she put the green (her lucky color) bit of wood with 8 ( her lucky number) on it, on to the hook..."
After "...and went in..." consider adding (falls over a large object).
The suspense has been built up by the use of glosses in this possible future time and space where a girl, seemingly vulnerable - not knowing what to expect - is about to experience something unknown.
A "gloss," when used in this context, refers to a note which is made to give more information to the reader to ensure he or she understands the setting. The opening sentence of this potential story is seemingly random and a flashing green light has many possible interpretations. One possibility could be using a gloss to explain what is happening immediately before the light flashes. It depends on the writer's intention. Consider preceding the opening sentence with:
Theatre door. Woman waits patiently, uninterested in surroundings, passive.
Consider also adding "carelessly" as follows:
" ... she (carelessly) put the green bit of wood..."
In this instance, the green light is the most significant aspect and it is placed in the context of a theatre. The woman may be an actress, waiting for a scene to change. Usually a red light signifies a live performance of some sort and entrance to the set would not be allowed until the green light comes on.
An opening sentence like this could save the significance of the "wood with 8 on it" for a later dramatic event and the reader will recall the careless placement of the wood perhaps when someone is murdered with it or it is found, suspiciously, in someone else's possession.