Seek out training programs offered by accredited schools that participate in the Stafford or Perkins federal student loan programs, neither of which approves loans based on your credit history. As long as you are not in default on other federal student loans, you cannot be denied a Perkins or Stafford loan because of bad credit.
Find someone who is willing to co-sign a private student loan. Keep in mind that if you default on the loan, the co-signer becomes responsible for paying it off. This can harm your relationship with the co-signer.
Delay your training until you can improve your credit score. Review your credit reports and dispute any errors. Contact creditors and work out payment plans to clear charge-offs and reduce balances. Don't apply for new credit, and keep current with open accounts.