This page is mainly inspired from the noobs-anonymous FAQ.

Error message location
When asking for help it's very helpful to provide the error message to your question.
Usually it can be found in the console after scrolling up a bit(pgup or mwheel).
Hunk_Alloc failed
This error occurs when quake tries to allocate more memory than it's allowed to use. (Happens on big maps like b0 for example)
Solution: Increase com_hunkMegs.
Client/Server game mismatch
You miss file(s) needed to connect to the server. The server may use a different version than yours. For example: current version is 1.48 but a server is running on 1.47.
Solution: Get the needed file.
How to bind certain keys
Quake is designed for the US-keyboard layout. Using a different layout may complicate binding some keys.
Solution: Go to the controls section and bind the key to retrieve it's code.(cnq3 only?)