If you are using Responsive Web Design, use meta name="viewport" tag to tell the browser how to adjust the content. If you use Dynamic Serving, use the Vary HTTP header to signal your changes depending on the user-agent. If you are using separate URLs, signal the relationship between two URLs by tag with rel="canonical" and rel="alternate" elements.
Do not be fooled by those traffic sellers promising thousands of hits an hour. What they really do is load up your URL in a program, along with a list of proxies. Then they run the program for a few hours. It looks like someone is on your site because your logs show visitors from thousands of different IPs. What happens in reality is your website is just pinged by the proxy, no one really sees your site. It is a waste of money.