How to do a certified translation?

Start by translating the material into the target language or the language it has to be translated into. Then, place it on your letterhead for official presentation. Lastly, add a certification statement on the last page of your translation. Do not forget to sign and date it. To make a certification statement, you can start by stating your full name and saying that you certify or attest that the translation is accurate and complete in accordance with the original text. There are various ways to provide the attestation depending on the context. Here's a sample;

D&T Translations, as a professional translation agency, certifies that a copy of a document entitled “…” belonging to … has/have been translated by our qualified contract translator who is fluent and competent to translate from … into ….. In our best judgment, the translated text truly reflects the content, meaning, and style of the original text and constitutes in every respect a correct and true translation of the original document.
Address, Date and Signature.
If you prefer, you can also choose to add more contact information.

Please note you should not do your own certified translation. Neither can your family or friends. US and foreign government and academic agencies and institutions may reject your certified translation if they learn that it was certified by you or your family. To be 100% safe which is always better than sorry, you should use certified translation services.