Any ideas for writing a good Media Release?

Hi Flutherist!
So I have a business – I’ve had it for three years and it’s doing very well however I’ve recently taken on board people that need marketing done, PR releases, these are people who work within the entertainment industry such as up-coming presenters etc. I’m needing to write up some media releases to send out to TV companies, magazine companies to get articles about said ‘presenters’ etc, – however I have no idea how to write an effective press release and am not in a position to hire someone $2000 to do the campaign for me. Is anyone on here in marketing or a PR person, any tips on how to write a well worded campaign that will help get my artists interviews? Any do’s and dont’s – any online sites that can help – I can’t find any and I feel I’ve exhausted my googling. Thank you!