Here are the templates we always suggest:

Initial follow up:

Hi <first name>, just noticed you left some items in your cart. We still can honor those prices. Did you have any questions? Reply to this e-mail and we'll get right on it.

<list product image(s)>(please disregard this email if you already placed your order)

Finish Checkout<links to domain/cart>

Another follow up:

Hello <first name>, you might still be thinking about buying <list products>. Would it help if we offered you 5% off? Use this coupon: <coupon code> and save!<optional: list product image(s)>OK, Get me 5% off<links to domain/cart>