Cross-Selling is big on the agenda for professional services firms and has been for a number of years.  It is sometimes easier to put the theory and strategy in place rather than execute.   I read an article that was actually published a few years back that brings to life a brilliant river vs canals analogy that explains why it is tricky for many professional services firms.

Firms Behave Like Rivers:

• Life in professional services firms can be predictable. 
• Firms follow a natural path of least resistance towards practice/sector-led life.
• Like a river meandering and cutting the soft soil of its outer banks on its way to the ocean.

Collaboration To Cross-Sell is Like A Canal:

• Collaboration to achieve cross-selling is a bit like channeling water in an unnatural direction.  If done successfully, it can be ground-breaking.
• The Panama Canal was built over the course of many decades and cost millions of dollars and cost a number of lives.  It is now used by 14,000 ships each year and cuts down the journey from Virginia to California from five months to just two weeks!

The big takeaway being that implementing a cross-selling strategy at your professional services firm is going to be uncomfortable.  It is going to take time and a lot of chipping away, but it will be game-changing when you get there.