The most effective legal marketing in the near-term is that focused on existing clients and referral sources. My premise is simple, clients know you, have used you and they like you (presumably, or they would no longer be your client). Referral sources have already referred clients to you, and (assuming you have thanked them) will likely do so again. So, marketing aimed at enhancing and developing these existing relationships will provide the best chance for new business.
That is not to say that one should not also focus on developing new clients and referral sources to replace those that no longer need your services, and/or those that left for whatever reason. It is just that this marketing approach is more long-term, as relationships need to be developed.
Tom Collins has a great post over at dealing with four basic strategies for pursuing new opportunities. They are:
*Get there first with the most
*Go where they aren’t
*Use a niche strategy
*Create new value
I particularly liked how he makes these basic strategies applicable to law firms with his reference to the next Sarbanes-Oxley law, determining unmet needs of prospects, developing a niche to service those needs, and adding value such as better service. Take a look.

Firms should plan their legal marketing efforts to address both near-term and long-term business needs.