These loans are considered for people with a not favorable credit history. Hence, lenders will be lending their time and money with a person who has the reputation of a troubled credit history on paying his loans.
The lending investor usually formulates a kind of strategy where people with a bad credit would have to endure higher interest rates and a shorter period of time for repayment.
To improve your credit history you should make your payments on time. You could also pay the total amount of the loan in full as fast as possible. This will serve you for the purpose of re-establishing your credit standing and in getting faster application approval in future financial transactions. Make sure the lender company has a good reputation.