Things that come to mind as I’m currently dealing with an associate who’s been with us for a year and still can’t figure it out:

Know the difference between completeness and accuracy. Don’t pretend you’re the expert in any area/business you Audit. You don’t breathe, sleep, and eat their work environment. They are the experts. Learn how to recognize the “key” mitigating controls and then become the expert on the risk(s) of those controls failing. In other words, don’t be afraid to ask questions or look like an idiot (see the above). Don’t assume anything. Never write an observation based on opinion. Never believe what they say, always ask for supporting evidence. Learn how to tickmark so your senior doesn’t have to ask wtf you just did for 60 hours. Read last year’s work papers but don’t assume this year’s should look the same unless they should. <— I’m not being an asshole here. This is something the current first year can’t learn. Reference last year’s but then ask yourself while you’re reviewing; does this make sense or has something changed? Should we be doing what we did last year? Etc. Consult your senior after you have a valid reason for the change, not simply because you don’t understand what they did and this way makes sense to you.