This is a great question. A transition I myself had to make several years back from having a background in civil engineering, into becoming the CEO of the UK division of a Canadian Software company.

There's no real one answer, but remember when its comes to sales/accounts you've got to make sure your voice is heard the loudest. If you're going to email people saying "I would like to change my career", I'd imagine most would pass as it sounds like more effort on the employer than the potential employee.

A good way to start would be to think of creative and different way to reach the 'decision maker', thus demonstrating your acumen.

I'd recommend teasing out the typical characteristics expected of an Account Manager from your current role and apply them. Oh, and be super knowledgable on the product. We used to get 'experienced' accounts managers apply, but hadn't bothered to work out what we do.

Best of luck. Happy to share with you my experiences.