Most loan or credit card companies use a technique known as credit scoring to assess your application.
A decision to provide credit is based on the details provided in your application and information provided by the credit reference agency. If you do not pass the credit score required by the lender they will either refuse credit or may offer you an alternative offer which reflects the risk of the debt not being repaid. If you are turned down by one credit provider it may be because they operate strict criteria and so it does pay to shop around.
Find out your credit score.