Use common sense!
This is the most important rule of all. Don't live by the letter of the rules, think about the meaning. This is neither kindergarten nor law school, so don't go on technicalities and loopholes. If a rule says "Don't post any copyrighted material here." then this includes posting links to places where this rule is broken.
Forum posts lack a lot of non-verbal information, like facial expression and other body language. Sometimes you can't tell if the other side in a conversation is joking or dead serious. Cultural differences might make that even worse: You might make what is considered a funny joke where you live but insult somebody to the blood without knowing. If uncertain, start from the best assumptions. Tell somebody if you feel insulted (best via PM) and ask him not to do it again. Stay nice and calm. Some people just don't get along with each other. If you find somebody like that, try to stay out of each other's way. And use common sense.
We do not tolerate using aMule to break copyright laws. Should you reveal yourself to be in conflict with this rule, you will likely face a ban, or at the very least, have the relevant posts deleted. So please do not post any links / screenshots / examples containing this kind of material. The only exception is content of which you are absolutely sure that it is in the public domain or free software (as in freedom). Once again common sense is needed.
Follow the moderators!
If one of our moderators (including devs & admins, take a look at the list if unsure) tells you to do something (regarding behaviour in the forum): Do it! If somebody edits your post: Don't just edit it back, it was edited for a reason. If you don't understand why it was edited or why you shouldn't do this or that: Don't start a flame war, ask the moderator involved in a PM. Just reverting moderators edits tells us that you know you've done wrong and don't care. This behaviour will get you banned in a heartbeat.
Post to the right forum
A problem during compilation will most likely be right in "compilation problems", feature request go to the forum of the same name. Think about what you want to say before starting a new thread.
Read the sticky posts
Sometimes there are common problems / questions which are then put as a "sticky" or "important" thread in a forum or even as a "global" in the whole forum. Read them before posting!
Don't takeover somebody elses thread. If you think you are experiencing the very same problem for the very same reasons you can always post a "Same here" with additional informations in a thread. If unsure start your own thread. And no, "aMule crashes because the code is buggy" isn't the same problem.