Do I now sit back and just wait for some traffic?

Right boys and girls, here's my story. I have website - usual scenario right?

The website is packed full of keyword rich content. I update the site (content wise) twice a day with news & features relevant to my niche.

Each page has been optimized as follows:

1. I always populate the meta Title, Description, and Keywords

2. Keywords are densely embedded in each news / content page (I use something like a 5-10% keyword density). I try to ensure that keywords are higher up the page, usually within the first paragraph.

3. I always link to other content pages within the site - the link text is usually the keywords.

4. I give the news picture a keyword rich Alt tag

Other than the above, I have starting link building with other relevant sites in my niche (one way, not reciprocal). I probably have about 10-15 inbound 'relevant' links from sites with a PR of at least 3/10.

The site was registered with google about 4 months ago.

I have an opt in list box on the site which is prominent of all pages. I use the list to drive traffic in the form of a weekly newsletter. We have explored social media and get some traffic from twitter, facebook, digg, and reddit.

Can anyone see a hole in my strategy? I'm keen to understand whether there is anything fundamental that i'm NOT currently doing in order to drive search traffic.

Thanks in advance