Bad credit when you didnt have credit to begin with?

Since you never used credit card, chances are that some incorrect items are entered in your credit report. You need to pull your latest credit copy and review each account. If their are some accounts about which you were not aware of, you need to call the original company and make payment arrangements. Otherwise, they need to be removed from your file, since they are hurting your scores.

You can obtain a free credit report from all three credit bureaus once per year (or when you have been denied credit) at https://www.annualcreditreport.com/ . There is no fee or program to sign up for to obtain your reports. You can print the reports, go through them line by line and dispute anything inaccurately reported online. It takes about a month to get inaccurate items resolved.

You may also want to make sure there has been no identity theft - make sure there are no reports on your credit reports of accounts opened in your name, with another user on the account.

Clean your reports up and then start adding some accounts to it slowly.

Yes it is very important to maintain a clean report as credit report gives a detailed information of your financial transactions. Hence it is advisable to pull up your report regularly to check your accounts. Under FCRA, consumers are entitled to request a free report every year from the three bureaus. While requesting a copy of your free report you have to provide your name, address, SSN and DOB.
Once you receive your report, analyze it properly to check whether there are any mistakes or not. If there are then dispute it with the bureau.
Your credit report reelects your creditworthiness.So, maintain a clean credit report.