The Professional Services sector has in each discipline, a number of very large firms because there is an inherent advantage to being able to offer a wide-range of complimentary services to a client. It is another benefit of having a broad diversity of talent within a firm that they are able to deeply understand the needs of the customer right across their business. 

Because this arrangement is beneficial to both the client and the supplier, it is clearly sensible for professional Services firms to harness this, often viewed as 'cross-selling'. However, many professionals dislike being perceived as selling, they like to get on with the job and deliver value to the client. 

This could suggest that getting professionals to sell is the key; if a firm can  be more sales-oriented a wealth of cross-sales and growth can be achieved. 

However, Frank Carone, Executive Partner at Abrams Fensterman in the Forbes article below looks at the issue from the buyer's perspective and makes driving the client's success the priority. 

The client couldn't care less about their supplier's growth targets and they really don't want to be "sold to", they are too busy trying to reach their own KPIs. However, being helped to get there clearly benefits all stakeholders. 

For a diverse firm to be able to service a wide-range of needs efficiently, they need to demonstrate that they have the ability and experience that the client requires across the relevant disciplines. They need to be publicly addressing the issues that clients are are confronting to build trust in services that they are not currently delivering to the client.  

Then diligent professionals can drive growth without selling but by assisting their clients and making them "highly appreciative" that you can "enhance their wealth".