Most students will make one of two mistakes when job-hunting:
1. They won't use LinkedIn whatsoever
2. They will use LinkedIn incorrectly
The following is a great article by a student who managed to get into a major IBank (GS/MS/JPM) from a "semi-target" school through very targeted and effective use of LinkedIn. I've added some additional comments and perspectives about what he did right, what he could have improved, and what not to do when using LinkedIn to get an interview.