There are basically three ways to get new business:
It’s generally easiest to generate additional business from current clients because they know you; they know how you do business and the value you bring to them. Chances are they haven’t given you more of their business because you haven’t asked them.
Take a look at your client list. Identify the needs you currently meet for them and then for each client, list out additional needs you and your firm could provide to them. This will give you a good starting point from which you can build your marketing efforts to generate additional business.