There are two ways to get people to subscribe to your email list;
1. Double opt in (where people have to click a link in a verification email to be added to your list)
2. Single opt in (where people are added the moment they enter their email address)
If you want to get a better email sign up rate - switch to single optin.
Now, this won't necessarily equate to getting a higher quality email list, of course.
But it will get you more leads.
I've been in this game for 20 games and swear by single optin.
I personally use Getresponse to build my list and they let you know do single opt in, no problem.
Even a low quality lead has some value.
The harder you make it for people to join your list then, yes, it's true - the more qualified they will be.
But think of how many potential customers you might be losing.
I prefer to do my qualifying and filtering in the email broadcasts I send out.
Let your subscribers self-select and qualify themselves, by the actions they take on your emails, not by the hoops you make them jump through to join your list in the first place.
Okay, onto the next method to boost your email sign up rate;
Be Consistent in Your Wording