My first year of law school I was eligible for private law loans at a pretty good interest rate. The next year I was turned down, and the only bad thing on my credit report was that I was over 30 days late on my Kohl's charge once!! I could have gotten a cosigner, but decided instead to make due with federal loans. If that's not an option for you, try to find a cosigner. You might actually get a better interest rate if you can get a cosigner with really good credit.
Oh, by the following year, I was eligible for law loans again, but that old Kohl's thing is still on my credit report. I think what made the difference was that between those two years I had paid off a bunch of my other credit cards.