Documentation is the key. Having everything organized and documented goes a long way with the auditors.

Are you talking general safety audit, or for insurance purposes....short answer yes, I do tons of audits

Yea, I have a custom checklist I use that I work through when walking a building then just take pictures of what I see.

We do these as a company, with corporate safety and at least one other EHS manager from a different site. This allows us to look at the overarching corporate standards and allows the EHS managers to view the other processes outside of their standard plant.
As far as documentation, I always rely on pictures as well as the audit checklists. The pictures really help to remind you what you saw at the time of the findings, which helps with your memory recall when you finally sit down to write up the report at the end of the audit. It is also difficult for the site to argue that the condition didn't exist when you have the proof right there in front of them.