A first job can be hard to land. Are you looking for jobs that you are qualified for? Play up any internships you had. Are you looking in areas that have jobs that are introductory? It's not nepotism unless he's your uncle or something, but it is normal and fine for your mentor to help you find a job.
Look for personal contacts that can help you get through the endless blitz of resumes. Look for a company recruiter on linked in or the web that hires people with your background, connect up with them, tell them you might be a good candidate. Respond quickly to their email. Look for user groups in your area, go to them. Ask your profs. Doesn't your college have a job counseling office, usually you can keep using it even after you graduate.