The first thing you need to know about online lead generation is that it is not just about traffic numbers.
If you have a terrible call to action / value proposition you are not going to be able to generate very many online leads no matter how much traffic you get.
So the first thing you need to do is look at your call to action and analyze if you think it will generate leads. Then test it for a short while and see what percentage you get to become a lead. The fast way to test your offer is with buying adwords traffic. You may need to try a few offers and you really need to think like your prospect to do this well. What do they want?
Then, once you have a great offer and a way to collect leads, like maybe a CRM, then you need to start getting traffic to the offer.
The best online lead generation traffic is inbound traffic. That means it is people that are finding you and coming to you via other sources. It may be via search engines, social media or articles they have read on another site. The reason this traffic is so good is that they are already interested in your product or service and are out actively looking for information. This is going to be a much higher quality lead.
To get this kind of traffic, you need to use a variety of inbound marketing techniques. Blogging with your keywords in mind is just one of the very positive steps you can take to attract more targeted leads. Business blogging has a great ROI when you keep it up because it continues to get stronger and keep increasing traffic over time. It also either increases your content on your site, if it is internal, which brings in more traffic. Or if you do an external blog it will increase inbound links to your main lead capture website and improve the traffic and performance of that website as well.