"Not Being able to show the required inspections and AD compliance in the aircraft logbooks
Not being able to tell when the inspections expire
How to tell if a piece of equipment is necessary for flight in a particular airplane.
Lost Communication procedures - Read the regulation and don't forget the last sentence of the regulation "on each route segment"
Maintaining at or above mandatory altitudes printed on approach chats.
Not identifying NAV aids, in particular the DME
Not testing both COMM radios prior to taking off into IFR
Never resetting the heading indicator after taking off.
Not knowing that there are some airports that can never be used as an alternate or that some have different minimums or that some approaches are not authorized at the alternate airport.
Departure procedures - How to get out of an uncontrolled airport under IFR. In particular what procedure to follow.
Not paying enough attention to the back side of the IFR approach plate (Airport layout side) in Jeppesen approach charts
Not being aware of where you are on the approach until it's too late.
Memorizing the approaches so that it's more like an approach type rating rather than an instrument rating you're getting.
The principle of operation of all the navigation receivers you are going to use and in particular how they can fail. Note the difference between how the VOR and Localizer work. They are totally different so when you're doing your VOR test, it's not testing the Localizer at all."