The first and most obvious thing to check when you're getting low open-rates are the subject lines of your emails. Would you open an email with that subject line if someone else sent it to you? The first thing you have to work on are your subject lines, do some research about creating attention grabbing subject lines.
Make your newsletter like a TV series you never miss, one that you never miss not even 1 episode. Your subscribers need to be waiting for your next email. You can achieve that by offering value in a series format (part/day 1, part/day 2 etc.).
At the end of each email mention that the next email will be sent tomorrow same time. Give them a teaser at the end of each email by mentioning what the next email is all about. For instance: "watch out for video 3 tomorrow where I'll show you 5 ninja strategies that will help you..."
Make your subscribers get used to opening your emails from day 1. After they put their information in the squeeze page don't send them to the download or whatever they're getting for free. Instead send them to a page that tells them to go check their email to proceed.
At the beginning of that email introduce yourself, add a short bio (a story works better), then give them the freebie and at the end say something like: "hit reply and let me know a little about you and your business/goals..."
That way you get to build a relationship with them, send them valuable content and pitch once in a while, but you simply need a way to make them eager to read your next email that will make it a lot easier for you to get high open-rates. Always make sure you're offering value.
Hope that helps.
