Using a landing page with a free offer of something valuable is a great way to drive traffic to your website. Here, for example, is what has happened in the last week to the views of one of my landing pages . . . it is our-performing everything else on the website! This is the second week of the offer by the way so the number actually went down from the first week.
What is a landing page? (Here's another example) It is a page on your website that is meant to do one thing. In this case to offer a free eBook: Private Practice through Contracting if the interested party will provide their email address. That's it.
What is the value to you? Well, there is the obvious . . . being discovered. Now more people will know you exist and if they find your content useful may come back again or even use your services. However a more important one is that their email address allows you to keep them on a "mailing list" and to begin to send them follow up emails.
These follow up emails will provide more valuable free stuff--usually blog posts, insider tips, your own experiences and thoughts. They continue to get value and build a relationship with your "brand." These emails may contain ads for things you are selling. They may have links to other content on your website that also has ads of a sales link. Eventually, as your email list subscribers trust and value your content some will become customers.
The one "hidden" challenge to this process is that you still have to get the attention of people who would like to visit your landing page. I have found my account at Psychology Today to be a good market for Psychology-related offers. Marketing the free item is critical once you have the landing page ready to capture the emails and provide the free stuff.
By the way . . . I personally use Squarespace for my website, and Mail Chimp for my email list and delivering the automated follow up emails. There are other options of course but I find these work well if you have some understanding of how to engage with technology. I also find that they are popular enough it is easy to find tutorials and articles on how to set up your process.