Start by looking at any student loan debt you have already accrued. Reduce your payments to a manageable amount if your lender will allow. Make as many on-time payments as possible in the process of applying for more loans.
Consult with your school's financial aid counselor about bad credit student loans. Ask your counselor about federal assistance options that may still be available, or some private companies that offer student loans.
Try first for loans through the federal government, since these require no credit check. Apply for a loan through a private company if you already have several federal loans or cannot get another federal loan for some reason.
Find a co-signer who has a good credit rating who you trust and in turn trusts you. Ask your co-signer, who can be a friend or family member, to sign a promissory note with you to obtain a loan.