When you start flying in a multi-crew environment, it's easy to cause distraction to the other pilot, and yourself.
You can help avoid causing distraction by being aware of when it's appropriate to ask non-essential questions, and make conversation etc.
Changing radio frequencies is one time the non-flying pilot needs concentration, not only do they have to remember the new frequency, but if the frequency is congested, have to remember to 'check in' with the controller.
The last thousand feet before leveling off is also an area where both pilots need to be aware, even when using the auto-pilot. Airliners climb and descent rapidly, and if the auto-pilot doesn't capture the altitude, quick correction by the pilots can avoid a violation or safety concern. Aircraft flying in RVSM airspace (reduced vertical separation minimums) can be 1,000 feet apart vertically.
A 'pilot's discretion' descent is a clearance where a descent can be delayed until the pilot's decide to descent, this is useful to save fuel by staying higher, until a steeper rate of descent is needed, and also allows staying above weather until necessary to descent. However, you have to remember to descent and distractions can put it out of mind, creating the need for a very steep descent later.
A crossing clearance is extremely important too, like a pilots discretion descent, it allows the pilots to decide when to start the descent, however in this case the aircraft must be at a particular altitude, at a fix. Chatting after getting such a clearance can cause both pilots to overlook starting the descent, which could be several minutes after receiving the clearance. This can make it difficult or impossible to reach the altitude in time. Some approaches require a particular speed and altitude at a fix.
During the descent and approaching 10,000 feet is another critical area, below 10,000 feet is a speed restriction of 250 knots. This usually requires a slow down ahead of time, and any distraction could lead to descending below this altitude at too fast a speed.
Airline procedures call for a 'sterile cockpit' which usually is all activities below 10,000 feet, during this time all non-essential conversation is not permitted.
With some experience and awareness, it's possible to help avoid creating distractions, by saving questions for a more appropriate stage of flight, and allowing full concentration with clearances and level offs.
