1. Back Link Efforts / PR Building: You should market using well written content that will read well as not to reflect poorly upon your brand, most firms will have an in-house writer. However, there are many writing services available for smaller companies that can produce well written articles to market with.
You should focus the majority of their back linking efforts on targeting key words / brand to the main site and the corresponding subsections. Your competition is extreme and over time you need to build up the PR value. In some case we see competitors ranking for 1000+ search terms. So keep your efforts focused on your main site and subsections. Avoid micro sites unless you really know what your doing in terms of building SEO rings.
2. Cited Sources / Press Releases: Any time you submit press or any other high value news source make sure your proper name and website address is in the content. These services are valuable for key word building. DO NOT LINK TO MICRO SITES! I have witnessed time and time again companies trying to get an upper hand with Google by creating micro sites and then linking to them with real news releases. Not only does this dilute your link building power, but more importantly you can confuse the Google because it matches cited sources.
3 Google Places impact: If you’re a business with an office this is a must.
4. Adding new content: Google likes to see new content added to the main website. If you are targeting for example a weddings, its better to make a small group of high quality pages about that and post them to the main site verse posting to a secondary site. It will rank faster and help your PR value.
5. Social Media : (Face Book / Twitter pages) Its ok to point links to the secondary blog sites. However, you would typically see many posts back linking to the main corporate site page. Again add new quality pages to your main site and talk about them.