In airline operations, for almost as long as I can remember now, it has been standard practice for both crew to listen to the clearance as it is received. On so many occasions that I have lost count of, this has resulted in one or other of us querying some aspect of that clearance, whether it is the name (foreign accent and pronunciation) altitude/level, or squawk; the ambiguity has been caught, and resolved.
In corporate operations, I frequently had to 'push' the F/O to clarify the clearance after it had already been received, because he had taken the clearance on his own. Again, this frequently resolved some ambiguity that existed. More than once, the repeated clearance bore no resemblance to the first version.
Too often, even now, clearances issued during push or taxi are recorded when there are other distractions.
Not so very long ago, I was working in North America. The issue of lower transition levels/altitudes frequently caused issue for local crews when around the Caribbean, where the levels are frequently reminiscent of those in Europe.
Standardisation could benefit more areas of operations than just the transition altitude. However, that is unlikely to happen in the short term. Better briefings from companies for crews operating outside of their usual hunting ground would help relieve a great many problems.
That works both ways. You shouldn't go swanning off to the US/Canada without thinking about regional differences and expectations, any more than North American crews should simply arrive in London air space, to suddenly be confronted with strange hitherto unheard of clearances. A frequently heard query over London being a US major querying a level such as descend to FL7-0 as FL7000feet? Crews from both sides of the pond are frequently getting it wrong. Often to comedic effect, until the enormity of the error becomes apparent.
One area frequently mentioned in the previous postings, here, is the clearing up of confusion on the ground. A big problem can often be not realising that there is any confusion until later. That smacks of not briefing properly. I'm not talking about laboriously briefing every single bit of a departure; as a senior training captain once said to me- 'I can read the bloody plate, tell me about the bit that isn't written there'.
Being cleared to quite a high initial flight level on a departure may suddenly seem strange when the norm has been initial levels in the single thousands of feet altitudes. A badly scrawled clearance, taken in isolation, inadequately briefed and understood (I said something, he heard something, but was it the same something?)
The traps are all there, and none of us are immune.