Email marketing is a powerful tool that can extend your reach beyond your website and create new sales opportunities. If you simply sell to customers when they happen to visit your site, you have an all-or-nothing chance of making a sale. Should they leave without signing up for a class or birthday party, there’s no guarantee they’ll return later.

But when you build an email list of current and potential customers, you can reach out repeatedly to your prospects with targeted messages.

Here are five ways to integrate email marketing into your website and stay in touch with your best prospects:

1. Build an opt-in form on your home page.
Perhaps the easiest and most common way to create a list is to integrate an email opt-in form into your home page. To get attention, place your form “above the fold,” so visitors can see it immediately and don’t have to scroll down.

To get an opt-in form code, you’ll first need to sign up with an email marketing services provider, which will cost you up to $20 a month. The cost will likely increase if your subscriber list becomes larger than 5,000 members. This type of company allows you to collect email addresses, manage your lists and send messages to your subscribers. Once your account is set up, log in and follow the instructions in the company’s help section.

Related: Email Marketing is Not Dead (Video)

Here are a few things to keep in mind when creating an opt-in form:

• Generally, the less information you require to opt in, the more sign-ups you’ll receive. Most webmasters find that requiring only an email address and first name — or even just an email address — results in the highest opt-in rates.

• You’ll also get better results if you offer a bonus for providing your email address. I have found  that delivering a coupon code or early sign up for fall classes encourages more sign-ups.

• Depending on the email marketing services provider you’ve chosen, you may be able to split test your opt-in form. If so, try designing two different versions of your form that will be displayed randomly to visitors and will help you determine the most effective approach.

2. Include an opt-in option on your “About” or “Available Classes” page.
Don’t stop with your home page. Include a second opt-in form on your About  or Available Classes page. After all, visitors who arrive on this page have taken action to learn more about you and your Gym. Encourage them to get to know you even more by joining your email list.

3. Add an opt-in form to your checkout process.

Your checkout process can be another logical place for an opt-in form. If your customers are so invested in your gym that they’re willing to pull out their credit cards, chances are they’ll be interested in receiving future discounts and other messages from you.

For more information on integrating an opt-in form into your sales process, check with your shopping cart provider. Many of today’s top payment processers integrate smoothly with the most popular email marketing service providers.

If such integration isn’t available, you may need to use an external program or hire a developer to add the opt-in function. This shouldn’t cost more than $50 to $200, and you’ll likely find the extra effort and expense worth the investment.

4. Integrate an opt-in function into your blog’s comments section.
If you have a blog on your web site (and you should), you can integrate an email opt-in box into the comments section. You’ll be reaching people who already have demonstrated an interest in what you have to say.

Some providers of email marketing services offer blog-specific plugins that will let you add an opt-in feature quickly and easily. If your provider doesn’t have that service, you can purchase software for that function for about $100.

5. Consider a pop-up form.
Another option is to present opt-in forms via pop-up advertisements. Although some people find pop-up ads irritating, their continued presence on some of the web’s top sites can only mean that they’re effective for some marketers.

It’s a judgment call. If you do decide to put opt-in forms in pop-ups, be sure to track your site’s metrics carefully. What you want to see is an increase in opt-in subscriptions — without a corresponding increase in your site’s bounce rate.