Many factors can impact your credit score. Some more than others, but each aspect is just a piece of the puzzle when lenders look at the risk level.
More precisely, paying your bills on time will have a significant impact on your credit score. Keeping up with all bills will boost your score significantly.
The amount of debt you are carrying will also affect your score. The less debt you have, the better.
Credit cards can be a double-edged sword. Using them will help build credit, but too much will hurt your credit score.