Customers from your database usually have a name stored with their profile. Use it. An easy way to make your content personal is to address the email to their actual name. The difference between "Dear miss", or "Hello Els" makes a huge difference as an entry point. And as I’ve said: every bit helps.
Personalizing by the first name is just the start. You really can go wild. Just look at Amazon, one of the best examples of content personalization. You may be just starting out, but they've been at it for years. Their homepage is completely personalized for your profile. For example, you see reviews, recommended products, and your viewing history of previous products. It might be a little too ambitious for your company, but you can learn from the best, pick out what suits you and apply it to your website.