Your credit score is calculated based on certain criteria such as the history of your payment, the amount of debt you have collectively, the age of your credit and the mixture of credit (credit cards, secured and unsecured loans). In order to have a good credit score, you need to ensure that you pay all your credit card bills and loans on time. Do not exceed 50% of your credit limit on your credit cards or you will be considered credit hungry and this can cause your credit score to drop. Ensure that you do not have too many new credit applications as this can also cause you to appear as credit hungry to lenders and thereby have a negative impact on your credit score. Maintain a good mixture of credit that includes credit cards, secured and unsecured loans. But, ensure that you have a low debt so that it is easy to manage your credit score. Check your credit report frequently to ensure that all the information on it is correct as there can be incorrect information that negatively affects your credit score. 

If you have a bad credit score and are looking to improve it, you could try to pay off all your old debts. You can also take a secured loan against gold or property and pay off your outstanding dues to better your credit score. 

If you do not have a credit score, you can take short term loans and repay them on time to start building your credit score. You can also apply for a credit card and pay your dues on time.