Become a partner

Is your business linked to an activity or service that is typically related to another service? If so, you may be able to team up with another business owner and get more business together. For example, if you do web design, you might consider partnerships with businesses that offer copywriting services. You could benefit from their customers who also need web design services and vice versa. (Editor's note: A partnership as an affiliate with 1&1 is a great example of this!)
Get new business from current clients:
In many ways, your current clients are a great source of new business you can tap. After all, they already know you and think enough of your work to have paid for your services in the past. Explore whether or not they need new services. Even if they don't right now, a good contact will keep your name top-of-mind if they need your services in the future.
Use email to get your message out:
Email is a cheap, effective communication tool, and you can use it to get your message out to current or prospective clients. For email marketing success, keep a few things in mind: Many browsers today are equipped with spam blockers, so make sure your message doesn't get caught in the net. Also, give recipients a way to opt out of receiving future emails — an unsubscribe link that notifies you to remove them from your email list. For maximum value, keep messages short, simple and informative.