This is a really common question a lot of people ask when moving into consulting. A few thoughts from my experiences:
- You will simply NOT be productive if you are working 80+ hours a week for a sustained period. In 3+ years at McKinsey, touching every continent, I never exceeded 60 hour weeks for more than a couple of weeks at a time. Maintaining productivity in the shorter term in a very different prospective.
- Eating meals away from the desk helps - I was always more productive after a good meal break
- Try to build in a couple of activities a week (Gym, sports, music practice, etc) where you are completely offline for a couple of hours, and provides you something to look forward to. Your productivity normally increases when you are working to a deadline
- Try to work with others - working in a hotel room there can be a lot of distractions. If it's late and you are working next to someone you don't want to disturb your colleague too much
- Prioritise ruthlessly and ask questions like 'does this need to be done today', and 'will this change the answer'. Partners are people and are very open to these challeneges. New consultants are often afraid to ask these questions, but they are crucial in maintaining productivity
Hope this helps