IB: How to become efficient

I always try to think of things my senior folks may ask questions about / want to see changed and make sure that however I put together whatever analysis I'm doing, I can easily address these things (e.g. setting up my Excel work to be dynamic enough to handle the "what if we..." question).

Keep a book where you throw slides you particularly like so you can leverage them later (most banks have a ton of off-the-shelf stuff already, but this should be stuff you've had to create from scratch and could see yourself adapting for future books).

Ask questions at the front end of whatever work you're doing. Loop in anyone externally a project will require ASAP to reduce likelihood of someone else slowing you down.

Look at past books (whether it's a pitchbook, CIP, MP) your senior bankers have given the sign off on whenever you're creating pages from scratch - steal page layouts you know they've approved of before to avoid total reworks.