What is the best way to find resellers for our product?
If you've done your research and are, in fact, contacting the perfect business partners then I suggest calling them first. Sending emails that someone is not expecting can often times lead to no action because you are an unknown entity. Worse, many times your email may go directly into their junk email box or spam filter.
When you make a personal phone call, you accomplish two things -- confirming the name, title and email address of the right decision maker while making an initial introduction of yourself and your company to that decision maker.
Next, I'd suggest sending them a brief introductory email with a meaningful and compelling subject line along with a one-page attachment. The attachment should be professionally designed, sporting your unique brand and logo, along with clear, upbeat content with several calls to action.
Mark your calendar to check back with each lead in several days, giving them three to four business days to review your email. Even if you just get a voice mail, that's fine. Practice a short, upbeat message, saying you are following-up on a previous email and/or voice mail message. Indicate that you are seeking a face-to-face meeting, looking to schedule a phone meeting or whatever your ultimate goal may be.
Give each lead space and defer to his/her preferred contact time line and method (i.e. some folks like emails versus voice mails). Make it your business to know a bit about each company you are seeking business from -- well-educated salespeople are a happy surprise to most folks.