Besides paying your bills regularly and on time, the single most important thing you can do to show that you are a good credit risk is to know what's in your credit report.
Studies have shown that many credit files contain errors that can harm your credit rating, leading to rejections when you apply for loans, insurance or even a job. The errors range from simple human error to being mixed up with a similarly named person.
It's essential that you check your credit files and monitor your credit regularly in order to protect your good credit standing, even if you always pay your bills on time.
And if your credit needs improvement, checking your report will help you find any problems that can be cleared up. A correct credit report, paying your bills on time and the passage of time will ensure the highest scores.
You can get a free copy of your credit report from each credit reporting agency at AnnualCreditReport.com. Try getting one at a time and you spread them throughout the year. At this site, you will have to pay for credit scores.
If you'd like to get them together (credit score and credit report) go right to the original source: MyFico.com to get all three. I prefer MyFico if this is the first time you are checking your report because it's easier to read and you'll be able to see all the scores side-by-side. With AnnualCreditReport.com you'll get one (very long) report for each agency.
You could get your free reports and then use My FICO free Credit Score Estimator to get a ballpark credit score (if you're planning to get a loan or mortgage, you'll want the real thing).
It is a good idea to check your credit report once or twice a year so you keep on top of any problems that might creep in. You can do a quick review by using AnnualCreditReport.com to check one credit report every 3-4 months.
Once you get in the habit of checking your report regularly, it will take very little time because you are only looking for something unusual to jump out at you.