If you don't want to get an infraction, then you need to read the rules and follow them:
https://www.physicsforums.com/showthread.php?t=414380
Typically, first offenses don't get any infractions but they merely get warnings. Warnings serve to remind you of the relevant rules. The name "warning" sounds far too serious and it should be "notice" or "reminder" instead, but I think we're in the process of changing that. In any case, a warning should not be taken very seriously: it doesn't give you any infraction points or anything. They are merely reminders.
Now, the trouble begins if you ignore the "warnings" (or if your first offense is a very heavy one). If we give you a warning about doing something wrong, and you just do the same thing again, then you will be given an infraction. If you keep doing the same thing wrong, then you will be given more (and heavier) infractions.
Things that get an immediate infraction from me (so with no previous warnings) are
- Obvious crackpottery
- Insults
- Spam
- Posting personal information about another member (without permission)
- Trolling
So basically, these are things that you
know are not permitted without even reading the rules.
Some offenses that new people make (and that get warnings):
- Not posting homework in the homework section (note: if you are self-studying and you are solving problems from a textbook, then it also belongs in homework)
- Making a thread title that is not descriptive (such as "Please help me nowwwww!")
- Bumping a thread too fast or too much (you should try to bump only after 24 hours have passed, and even then bump only once)
- Posting a thread multiple times in different forums (if you have posted a thread in the wrong section, then just report it and the mentors will move it for you)
- Asking a question cold (see https://www.physicsforums.com/blog.php?b=3588 )
These seem to be the most typical things that new members do to get warnings. For a full list, you'll need to read the rules.