Have a great story / hook.
Reach out to outlets who 1) are relevant 2) write about Kickstarter campaigns regularly.
Determine why you want the press, pre-launch. It should either be for social proof for your "Kickstarter As Seen In Logo Banner" or to drive any traffic to a landing page to gather pre-launch opt-in emails.
That is explained more in these blog posts. Enjoy...
Most definitely. I actually highly recommend it so that you can collect emails before launching. This can be done through creating a beautiful landing page with content. Depending on your press approach, you could email writers or hire a PR firm.