Well, having been in several Reformed churches that did not grow (numerically for sure, and the spiritual growth was lacking in many areas as well), I can say one thing that many Reformed churches (Presybterian that is, I have no experience in the Reformed baptist world), big and small, seem to have a problem in the friendliness area. You walk in and you don't feel welcome. If you don't feel like there is the possibility of fellowship, it's unlikely you'll return and stay. This is not a church growth method--just simple common sense and principles of biblical fellowship that would be good for Reformed churches to make more of a habit.

Note: My experience is obviously limited to just that, my experience. This is not to say that all Reformed churches suffer from this. But I have come across many that do.

__________________
Joel S.
St. Paul's Presbyterian Church (Orlando, FL)
M.Div. Student, RTS Orlando, Oviedo, FL