What are some direct response internet marketing techniques to get online clients?

I have a website about web design and development. I created a website because I like to provide high quality website development services to all online clients but I do not have any ideas about website advertising and internet marketing. I found in some blogs about this "direct response internet marketing topics" but I do not have any ideas about it.
What is this direct response internet marketing? Do you have any internet marketing techniques that you think can give my website some clients for free without paying any advertising company?
Thanks You Very Much
