I am more than happy to help my students with their job search. But I am often surprised by a few common mistakes I see with regard to references.
Students, please take my advice when using references in applying for jobs. References can better help if you do two simple things:
a) Ask your references to actually serve as a reference. Don't make the assumption that someone wants to, or will be, a reference just because you had interactions with them. I just received a phone call from a prospective employer who indicated that one of my former students listed me as her reference. This student never asked me to serve as her reference but made an assumption that I would be a reference. (Recall the famous saying about what happens when you "assume"? I won't repeat it here.) The bottom line is that you should simply ask people to serve in this capacity.
b) For the people who have agreed to serve as a reference, inform them about your situation so they are prepared to talk about you. Personally, I like to have a copy of someone's resume or access to a LinkedIn profile. I also like to know career plans, the types of organizations that may be contacting me, and where someone is in a particular job search process (e.g., initial applicant, just had a second interview, etc.).
Do these two simple things and you increase the chances of references making a positive impact. You also create fewer surprises.