Maybe you feel some strictures on proofreading isn't necessary, but it is. We regularly see carelessly written press releases. Errors jump out at us, discrediting the message being offered. That's truly an unnecessary risk, but it's taken over and over again by folks who aren't able to get a little distance on themselves.
You've got to stand back, take a deep breath, and read copy anew, as though you've never seen it before. As encouragement, we offer Joan Stewart's blog post, "12 proofreading tips for press releases, blogs & other copy." It's based on Mickie Kennedy's experiences at eReleases.
Stewart adds four more tips of her own. She's a former newspaper editor, which is qualification enough for suggesting how to avoid distracting press releases.
It really comes down not only to grammar but empathy -- putting yourself in the reader's shoes, after you've gotten past the prideful notion you've created a worthy piece. You've simply got to read draft press releases anew. Don't just write it, glance over it and send it.
Remember, the temptation to shoot a news release out is greater at a computer keyboard than with paper. Don't yield to it!