How Can I Get a Lower Interest Rate on Student Loans?

loans

When I was ending my grace period after graduation college, I consolidated my student loans. I had most of them at 2.48% and a couple at the end that came in at 6.8%. When I did the consolidation, I finished up at 6.75%, then signed up for involuntary payments, so now at 6.5%. Is there anyway to lower my student loan interest rate?