Legal advisers that do not phone back give the appearance that you are working for them. Look at the quality of the people supporting your lawyer. If you do not see competent employees, chances are this person will not provide the service you are paying for. Most legal advisers charge clients based on the hours they put into a file. But good ones look at the value added and the outcome and adjust their bills accordingly.
Word of mouth is always an option.
Ask other successful entrepreneurs for the names of their legal advisers. After questioning a number of astute people, you will quickly put together a list of who to interview. You want a lawyer who can act as a team leader and who can bring in other legal experts when required. And the person should work well with other professional advisers. Just as with new employees, you will select your lawyer based on the compatibility between the two of you.