If you are considering doing a press release or have had a press release written for you then you might want to look at this free press grader tools. It can give you the basics of what you should have in your press release.
Now don't follow others marketers and just do a press release to get backlinks. A press release is designed to give the general public notice of important news. Just because you launch a new product, service, or website does not make it news.
Use a press release to actually post news worthy information for the general public.