Though the traditional way to improve the sight reading is just reading through a lot of music, I would like to know about some basic techniques to do it well. There is a major area I want to look into:
How to get the rightful use of 30 seconds (that we usually get before an exam)?
Another problem I always face is to take note of the dynamics in the piece.
PS: I'm a Grade 7 student
I only had one of those sight-reading tests once, but 30 seconds is enough to look for time signatures, key signatures, tempos, clefs (maybe less important for violin but there are things like false harmonics, pizz/arco, and 8va to look out for), and broader structural elements such as first and second endings, DS al Coda, and hum the first couple of bars to yourself. Since you stumble on dynamics maybe a few seconds to make note of highest and lowest point of piece.