Get a few DPEs together and we start telling war stories of past check rides and near death experiences. We are old and feeble and barely remember what we had for breakfast let alone what really happen three weeks ago but some elements of truth and commonality pop out in these stories.
Recent stories about entering and leaving towered and non tower traffic patterns have been making there rounds. Stuff like making right traffic at left traffic airports. calling in the wrong position in the pattern (or making the all to common call "turning left final runway XX), not following ATC instructions or telling ATC your east of the field when you are west, cutting off other aircraft in the pattern, landing downwind. The list goes on...
I can tell you to read and follow the regs and the advice in the AIM but I'll add a couple other thoughts.
1. Don't go near the airport until you are ready. Find the airport, get the ATIS or AWOS, figure out the active runway and the easiest way to enter the pattern. Take the time and THINK.
2. Double check your position from the airport before calling in. This is important! ATC needs to know your location to figure out how to sequence you into the pattern and keep you separated from others. At non towered airports, other aircraft need to develop the big picture too. Incorrectly announcing your position in relation to airport, runway or traffic pattern is a set up for a midair collision.
3. Keep your head on a swivel. You may be doing everything right but the other guy may not. If there is conflict in the air, its best to stay out of it.
A few years ago, an airliner got lost on an airport on a low IFR day. There was confusion on the frequency between the airliner and ATC. Thinking the Airliner was clear of the runway, ATC cleared another airplane for take-off. That pilot (hearing the confusion on the freq) declined the take-off clearance until ATC and the airliner knew where each other was at. Good thing this pilot declined the clearance. The airliner had made a wrong turn and was actually on the departure runway of the other aircraft. It would have been a disaster.