Writing my first cover letter?

If there is a hiring manager, that is always a good person to write it to, but if not the safest bet is to stick with "To Whom it May Concern". Make sure you keep it to one page, be brief but thorough; Stating things such as what position you're applying for, where you saw the listing for the job, any past experience in the work field (be brief though), and then any other tasks/qualities that you possess that may be an asset to the job. Then be sure to state when and how you can be contacted. And finally be sure to thank them for addressing your letter and that you look forward to hearing back. Hope this helps. And best of luck