Producers of television commercials usually try to present a clear call to action because they only have a few seconds of the viewer's attention. The same is true on a website -- you have a very short time to connect with people, so it's crucial to clearly define what action you hope for them to take. Here are some examples of typical calls to action (for a website that doesn't sell products directly):
Phone Call. If your major goal is getting the customer to pick up a phone, make it as clear and easy as possible. Don't bury the number on a contact page, but feature it on every page of the site. Use action language in your copy, like "Call us at 1-800-555-5555 today to speak with one of our expert team members."
Filling out a form. Web-based forms can be a great way to pre-qualify sales leads and collect essential information in a nonthreatening manner. If your goal is to have the customer fill out a form, be sure to communicate the value of doing so. For example, if you have an RFP form, you might promise a response within 24 hours. Keep forms as simple as possible and ask for only as much information as is really needed to handle the request.
Visit to a Physical Location. If your website exists to support a physical location and you want to drive foot traffic, give the customer a reason to make that visit. Use the site to promote special events or offer an exclusive coupon. Make sure the site offers clear, accurate directions to the location.
You can't determine the success of any marketing effort unless you know what the goal is. Making a clear call to action on your website not only communicates your value proposition to customers but also gives you an effective metric for success.