1. Have a plan. What kind of information will bring value to your customers? What information will encourage them to follow you, and keep you foremost in their mind when they need your product or service?
2. Have a Professional Website. Social media is about building relationships – your website needs to close the sale make sure it is relevant and current. Your website is what holds your brand messaging, value and calls to action. (Make sure you are using consistent branding elements, logos, etc. in all media.)
3. Start a business blog. Blogging is a great method for interacting with your current and potential clients. Additionally, search engines love to index blog content. Frequency of posting depends on your plans for the blog. If you are a writer or a speaker blog daily, most businesses can get a way with posting less frequently as little as once a month.
4. Create  LinkedIN and Facebook Page for business. Go where your customer is! LinkedIn and Facebook Pages are free and allow you to communicate regularly with people who follow your page. Encourage customers to like your page by offering incentives like giveaways, contests, discounts, etc.
5. Have a Twitter account. Engage it’s easy, fun and free. Before you launch your Twitter account think about what you tweet and how often? Consider following established Twitter users and learn from them.
6. Secure vanity URLS on all the major social media sites. Try and use the same name on every site. (and the same profile image!) Even if your plan is to focus on Facebook and Twitter right now and you will get to the other add-ons later, secure your name before others do.
7. Get your business listed on Google Maps. Go to Google Places for Business and register your business. Google will confirm that you are legitimate with a phone call. While you are it, do it for Yahoo and Bing too.
8. Create and Post Youtube videos. Videos can be easily embedded on websites, social networking profiles, email them, email links, etc. YouTube is the second largest search engine right now – get your company name in there. Reach the population who want to watch and not read. For those who want to read, transcribe the video content and add it as a linked page or as a blog entry (receive a bonus for additional search engine indexing).
9. Get a Flickr or Picasa account. Do you have photos of your business, products, staff, or samples of work you have completed? Let people get to know your staff and your products by posting them. This makes it easy for sales people to retrieve them while they are on the road too.
10. Interact and update often. Add relevant events, sales, services, news, photos and articles of note regularly. Stay engaged in your social media outlets. This helps customers and prospects see you are staying active, helps increase your rankings in search engines and helps keep you alert of achievements and industry trends.

Other Options that are helpful:

• Build accounts on social bookmarking sites: Slideshare, Digg, Reddit, StumbleUpon, Delicious, etc. Add your best presentations, blog posts on these sites so other people will see the value of your work then they promote it to others.
• Get on Foursquare. For businesses with brick and mortar stores Foursquare allows your customers to “check-in” via their mobile devices. Check ins generate exposure for your business. Each check in blasts to all their friends and shows their entire following that your business has something of value to offer customers. To promote use, offer incentives to your customers to check-in more frequently (discounts if they check in, free item after 10 check ins, etc.).
• QR codes. Used similar to Foursquare ins some case. The benefits of QR codes is they can be added to print promotions, signage, websites, etc. and they can serve multiple purposes. When a customer scans it with their mobile device they can capture all your contact information, website, phone number, Facebook page, etc. and now there are codes where the visitor can literally window shop with their mobile devise and purchase the item in you store front while your store is closed. So many possibilities with this as the technology increases.