Skim the passage that you will be sight-reading. Identify any potentially tricky rhythms and work them out in your head. Even in audition situations, you will have several seconds to look over the passage before you play it.
Set your metronome to an appropriate tempo, using the piece's tempo indication as a guide. Clap or sing the rhythm for the entire passage, focusing on staying with the metronome. If you make a mistake, do not stop. In an audition, you must continue playing even if you make a mistake.
Return to any passages that caused you trouble. Take a pencil and make check marks over the notes that fall on the beat. These check marks help clarify the rhythm. Clap or sing these passages with the metronome. With continued practice, you will find that fewer passages will cause problems because you will become familiar with common rhythmic patterns.
Set your metronome again. This time, play through the passage on your violin from beginning to end, without stopping for any mistakes.
Skim the excerpt that you will be sight-reading and identify any potentially tricky passages. Make a mental note of any accidentals, or changes in key signature.
Set your metronome to an appropriate speed, using the piece's tempo indication as a guide. Using your left hand only, work through the excerpt. Once you reach the end, mark the portions that caused you difficulty with a pencil.
Go over the difficult passages again, with the left hand only. Repeat them until the pattern becomes clear.
Re-set your metronome to the appropriate speed and play through the excerpt from beginning to end. Passages consisting of running sixteenth notes often pose problems to violinists. For these passages, break them down considerably. First, go through the entire excerpt playing only the first note of every beat. Next, play the first and second notes; then, the first three notes. Finally, play all the notes.