Good Practices
It's always a good practice to avoid having a QSO on a calling frequency – even if the propagation seems to be gone.There might be propagation even if you don't hear any radio traffic on the frequency at that moment.
It is also a good practice to always QSY after your general call. If you call CQ on a calling frequency and stand by waiting for calls, you're just creating more QRM to the call frequency, which is often already crowded with lots of stations calling.
You should avoid having QSOs on the phone (talk) on or near any of the calling or digital mode frequencies. If you QSY from 27.555 to 27.560 or 27.565 and your signal is 9+ in all of Europe, you're creating splatter to many listeners of the call frequency.
If somebody is calling a targeted CQ (CQ Outside of Europe, CQ Germany, CQ DX), only answer the call if you're in the targeted area.
Many 11m operators do not correctly understand the term DX. In Europe, we can consider stations in other continents (South America, Australia, etc.) a DX, as well as some rare countries in Europe that are not so often on air.
Good Practices When Working Activations Such as SES, IOTA, DX, etc.
Always write down the QSL info before calling. You can also listen for it afterwards or look it up on the Internet.
Never ask for the QSL info on a frequency if there are many callers for the activity.
If there are many callers, always call by using your unit number only. If there are no other callers, it's enough to call by stating your callsign. The DX knows his own callsign, so there is no need to repeat it before giving your own call.
When you manage to get the progressive number or in the case of an “in the log” system without progressive numbers, a confirmation that you are in the log, just confirm the progressive number or that you're in the log. Also give an RS report to the operator, if you have not done that already. (To count it as a real QSO requires RS reports to be exchanged.)
Some often Misunderstood Terms and Practices on 11 Meters
DX Distant X, distant unknown – On HF (11m) contacts to other continents and possibly to some rare DXCCs in your continent.
The Q Code QRZ QRZ is only used to ask the station calling you to repeat his callsign.
RS report To give an RS report there's no need to look at your signal meter. The RS report for a signal is given from the numbers on the RST scale, and each of those numbers has a meaning that needs to match the signal you are hearing.
73 73 means best regards. There are no 73's (best regards'); it is just 73 (seventy-three).