Ok, I got the traffic, what's next?

In my opinion, in order for you to get leads from your website, you need 2 things:

1) Traffic
2) Compelling content

Yes, you have done all you can to improve your web site's searchability, buying paid inclusion ad to generate tons of traffic to your website. If you do not have content, people will still leave your site in no time and you still have no new customer, no conversion.

You need compelling content to keep people on your site, to look for information, and hopefully they will request more info from you, sign up for your e-newsletter or to make a purchase on your e-commerce site.
Avoid wasting the traffic generated, before doing SEO or paid inclusion and improving your site's organic searchability, you should better your site content first. (Once searchers found that your site has nothing interested them, they will not click on your site later on even you have updated your content!)

Put aside e-commerce here (I will talk about it in another post), by saying compelling content, I mean the followings:

1) Professional attractive web layout - clean and consistent layout, not too busy, easy to read- attractive graphics- easy navigation- simple and easy to use user interface - good site ergonomics
2) Create positive client experience - with multimedia, full of useful features, easy to use
3) Relevant content - Imagine yourself go to a website after clicking on a sponsor link or a result on SERP but found no relevant content when you get there, will you leave the site immediately?
4) Just-enough information - short and precise. Depends on the industry and products (especially for expensive business products which usually requires longer decision process), sometimes too much details on the website is no good. People will be overwhelm by the info and get frustrated as they cannot comprehend. Provide just-enough information to generate interest in your products and to encourage people to contact you for more information. (However, for e-commerce site, you need to put enough info there so people knows the product enough to be confident to purchase from you.)
5) Quick loading - If your site takes forever to load, who has the patience to wait and browse?

Using web analytics tool, like WebTrends (I use WebTrends before and now using SurfStatsLive for my company's site and the Free Statcounter for this blog), keep track of on average, how many pages a visitor visits (Total # of page viewed/ Total # of visits). You can know how "sticky" your site is and can make plan to improve your site (or keep on doing what is working).

Yes, always need to improve the stickiness of your page. You want your visitors to stay on your page longer to look for info and at the end to convert them into a customer.