Know Your Stuff
When I was in management consulting, the best partners I worked with, were the ones who could not only 'schmooze' with clients, but who also knew their content i.e. what it was they were selling, in a reasonable level of detail. That may sound obvious, but you'd be surprised.
Many times, business development professionals are drawn in by the size of the opportunity or the profile of the client and believe that having the right sales support structure (e.g. a subject matter expert) with them is good enough to close the deal. And it can be - if your relationship with the client is already extremely strong, and the client is explicitly aware of what you're doing.
But there are also many other situations where the salesperson walks into a meeting with their content expert, makes an introduction and then sits quietly throughout the entire meeting, as the content expert conducts and manages the entire discussion.
That's kinda bullshit.
In my mind, you need to be prepared to at least two levels.
First, you need to understand why this work needs to be done. What are the business problems it solves? What are the core issues it remediates? How (big picture) does it resolve these issues? How will it change the client, short term/long term? How does it relate to their ultimate strategy? What can your client tell their stakeholders about how your work moves the needle for them?
Second, you need to understand how the work gets done. How involved is the work? What is the methodology? What kinds of tools and techniques are necessary? How long will it take? How intrusive on the client's daily life is your work? Does it require an ongoing change in their operations to ensure success?
Note that, as a business development professional, no one is expecting you to be the technical expert. That isn't your job. But if you know a bit about how the work gets done and are able to speak to the (higher level) intricacies of getting the work done, it makes you all the more credible in the eyes of the client.
Otherwise, you're just an order taker. And order takers don't get calls when the client needs to ideate. Order takers don't get called when the client needs a trusted advisor. Sure, you might close the deal sometimes, but will you get the call back?
Maybe it makes more sense to do the hard work and know your content a bit better. Enough to be able to talk to and around the issues. Enough to engage in meaningful conversation on your own with the client. Enough to relate the work to the ultimate strategy goals. Enough to not be perceived as an order taker.
What do you want to do?