For instrument pilots, the training emphasis is on flying approaches. The proficient pilot knows that there is a big difference between practice and actual instrument approaches. Weather is fickle and not always as forecast or reported. This is one of the easiest places in flying to grade yourself. If the weather was expected to be good and the air smooth, but it wound up right at minimums with some nasty wind shear turbulence, how were you after landing: Did you fill out the flight log with nary a quiver? Was the taste in your mouth pleasant? When you got out of the airplane did your legs feel wobbly? Could you go back and congratulate yourself on a well-flown approach despite the worse than expected conditions?
The answers to those questions could suggest how confident you are in your ability to handle whatever comes your way.
Training to proficiency has a lot to do with confidence, too. Being over-confident is not good. That leads to all sorts of bad things. But if you can't tell yourself, "I can do this," when starting on a difficult approach, then you are in trouble.
Which brings us to the airplane, an instructor and some proficiency flying.
I know a lot of old-timers who mightily resent having to fly with young flight instructors for a flight review or an instrument proficiency check. The flight review is left pretty much to the discretion of the instructor; the IPC has to follow most of the instrument check ride requirements. In reality, either one is mostly at the discretion of the instructor.
The fact is, most of the relatively young instructors are quite talented and are up on the latest. No matter how long we have been around, we can learn from them.
Before flying, the discussion needs to make sure the instructor knows what kind of flying you do and what things you might be called on to do, but don't often do in natural flying.
For example, most pilots flying heavier light airplanes do not often make power-off approaches. Yet if that greasy hunk of metal under the cowling stops making noise, a power-off approach and a spot landing will be required. To me this is an important part of proficiency flying. A pilot who doesn't know the power-off gliding characteristics of his airplane is not really proficient or current. Most of us don't do well at making ourselves practice this on a regular basis, so it should certainly be examined in organized proficiency flying.
For instrument pilots, partial-panel flying should be explored. Airplanes are getting ever-better backup systems but even these need to be explored and used.
Finally, what kind of airplane do you fly? Whatever it is, you can go to www.ntsb.gov/NTSB/month.asp and go to the query page where you can put in the make and model airplane that you fly, and get all the reportable accidents back to 1963. Experimentals are there too. For one thing, you might be surprised at the large number of wrecks, and you can reduce the time period explored if you want to look at less accidents. It is here that you can see where pilots just like yourself did enough damage to the airplane that you fly for the event to be classified as an accident. And if you examine the record with an open mind, you can come up with a lot of things to do on your next proficiency flight. Make that once a year for best results.