It's common knowledge in order to be successful online you need build a large, quality list through some type of Opt-In offer.
You see them on almost every site you visit, some type of form, whether from a pop-up window or directly on the site itself, that is asking for your name and email address in exchange for some type of offer (newsletter, e-course, free chapter etc.)
Here are a few tips on what to do and what not to do with your opt-in offer:
* You need to place your opt-in on your web page. However, where you place it is extremely important. Your opt-in should be in the upper left hand corner of EVERY page on your site.
* Always give a strong special bonus for people who opt-in. For example, "Sign up for my Teaching Newsletter and receive a free special report: How to Increase Reading Comprehension in the Classroom"
* DO NOT offer a free chapter of an e-book, a free e-course nor anything that might be purchased. Be creative here. If you give away something that might be bought, you are giving your customer an opportunity not to make a purchase.
* DO offer something that compliments and is related to the product you are selling.
For example, it is fairly easy to create a newsletter about your niche market. Your can start by offering a monthly newsletter on tips, articles, Q&As, book reviews, web sites reviews etc. related to your industry.
However... Avoid the daily newsletter, or anything daily. Normally any communication more frequent than once a week is simply overkill. Overloading your client is a quick way to have them become be less receptive to special offers or even opt-out all together.
Your opt-in list gives you a chance to drop in on potential customers for as long as they are still subscribed. The goal is to increase that list while not distracting the customer away from your product.