I came across an article posted on 1stwebdesigner that goes over some good principles for creating an online web design portfolio. I gave it a read because I recently completed a redesign for webDVLPR.com. Overall, I think I did a decent job adhering to their advice. A main point from the article is that web designers should maintain objectives when marketing themselves by overtly stating what kind of web designer he or she is. It is also claims that it is important for web designers to offer a realistic scope of services. Stay grounded! A lot of website design companies offer services that are out of their league, such as SEO. The third piece of advice states that designers should concisely describe themselves' on the 'About' page. Don't be wordy! No one wants to read about your entire life history.
Where I tend to shy from the article is in the social media aspect. A lot of time is wasted on these websites that could be productively spent with SEO. Yes, I do have a linkedIN account, but only as a symbol of "social proof". And yes, I did recently create my first Twitter account, but this is only to maintain relationships with those I have already made connections with. In my experience web designers get new clients, like any other company, from search engine results and word of mouth recommendations.