Writing an email to someone you've never met can be a tricky affair, depending on what you're contacting them about. Of course, there are several steps you can follow to increase your chances of hearing back, one of which is crafting a message someone might want to spend time reading. This isn't as straightforward as it sounds.
99u's Jocelyn K. Glei has written a great post on penning effective electronic missives, one that highlights a number of crucial points that can be easy to ignore. For instance, the most important aspects of writing an email are getting the person on the other end to read it and making sure the reply contains the response you need, minimising the back-and-forth. This comes down to carefully-worded subject lines and phrasing your questions so they can be answered with a simple "yes".
I think it also boils down to actually writing the email for the person you're sending it to. What I mean by that is firing off a form email to 100 different people and being shocked when hardly anyone gets back to you. It's always better to single out the people who you really want to get in contact with and crafting individual emails suited to them:
Step 6: Be interesting and interested. At the most basic level, this means do not ever send anyone a templated email. If you are asking someone to take the time and energy to reply to you, make it clear that you actually know who they are.
That doesn't mean being obsequious and singing their praises, it does mean talking to them like you are one human talking to another human. It's nice to articulate why you're interested in them. It’s also nice to articulate why they should be interested in you. Try to have a voice and say something funny, meaningful, or thoughtful—preferably all three!