Hi Amanda! Whenever I need to make a sales email, the first thing I always do is research, research, research. Find everything out you can about them, so that you can spark their interest initially by sharing something you have in common with them, or by complimenting their web design, or something of that nature. In the body of your email, make sure you're addressing their needs personally, and show them the solutions you can offer. Try to change your wording so there is less about you (the "I") and more about them (the "you"). And lastly, make sure to follow up after a few days

Also, never use a template when sending a sales email. They generally won't work well and the person reading it can likely tell it's a template you've created. Even if you don't sell them now, you're on your way to starting a relationship and a templated email won't leave any sort of lasting impression.
Hope this helps and best of luck!
-Hilary