Most big law firms are looking for a self-sustaining book of business. Usually, the Am 200 firms look for 600K to 700K plus, and the smaller boutique firms 500K plus. The very top Am 100 firms are generally looking for 1 Million plus. All firms are looking for consistent billing in these ranges, preferably three years or more.
Common ways to build your attorney partner book-of-business are networking in industry groups, increasing business with existing clients, and asking for referrals.
Other highly effective ways are going through your databases for potential leads, such as the law firm database you use daily, business journals, law360, and your emails-business and personal.
We all get swamped and either forget or pass over diamonds in the rough. Sometimes all we need is what is already there.