I used to work at McKinsey, and since then I've learned that one thing top professional services firms (basically MBB, Bulge Bracket, and Big Law) do (and virtually no one else does) is communicate.
That's right. People would make fun of us for being PowerPoint jockeys, but no client ever wondered what my team was doing, and they rarely questioned whether it was worth the cost. Why? Communication. Here is how we did it:
1) Clearly communicate the plan.
a) When you start a project, the client might not know exactly what they want out of it. If it isn't done before the engagement, the first week is always dedicated to figuring out what the client will consider success
b) Scope out defined deliverables for every week, and stick to those deliverables whenever possible.
c) Weekly or 2x per week progress upates -- never go dark, never leave them wondering whether you're making progress or not. this also preempts any issues that might come up because data isn't available, and it helps address scope creep in real time. If a deliverable is slipping, you communicate it before it's late and come up with a plan to get the project back on track
2) Clearly communicate the results. We already defined the problem in a way that we all agree on at the beginning. Now when you deliver results, you start by explaining how you solved the problem, then you walk thorugh the details. If you were doing weekly check-ins, no one is surprised at the end and everyone agrees that you solved the problem.
3) Throw in additional work for free, and communciate that too -- if you defined a very narrow problem, you solve that problem but then you probably will find 6 other related problems. By solving one or more of those other issues, you leave the client feeling like they got more than they asked for. BUT when you do this, you have to communicate and scope what addional work you're doing to make sure that the client will appreciate it. If it solves a problem they don't believe is a problem, it adds no value at all.
Even at McKinsey we sometimes failed to do this (especially during covid where communication was more difficult). The bigget failure mode was doing too much work that wasn't directly related to the client's problem, and then the team feels overworked and the client feels underserved. In most other organizations the failure mode is either defining the problem or providing regular updates.
If you're providing services of any sort for your clients or customers, use these tips and you will be in the top 5% of service providers.