Going to look at Duplexes for the first time tomorrow

Like the title says I am going to look at a few duplexes tomorrow. It's my first time looking at property for investment and I am pretty excited to get the ball rolling. 

I've looked around the forums for a while but haven't noticed if there is any type of a "checklist" of things to look at or ask when looking at multi-family housing.

I have put together a spreadsheet with all the info I could collect online so I could ask intelligent questions, but has anyone else seen (or used) a checklist or anything else for something like this?

Is there anything else I should be doing to prepare to go look at these? 

Any input would be appreciated. Thanks and wish me luck!