Can I edit other questions because of this?
First things first:
Can I add more points to the question? So the duplicity can be reduced and all the readers can answer a single question perfectly.
If you're talking about the duplicates: Please don't do that, unless you also change all the answers (cough please don't do that either cough). If your question is very similar to another one, don't edit the other one just to make sure yours isn't a duplicate.
You should rather tell us why yours is different.
What can I do if my question is very similar to others?
Some people feel it duplicate so they vote down or sometimes it leads closing a question.
Normally, if you post something that has been asked over and over again, downvoting happens, because people think "Ah, not this again!". And quite honestly, if you spend a couple of minutes searching the site before asking your question, you should have found similar questions.
This does not apply to every case, but for example questions about backups are fairly widespread and always produce more or less the same answers.
However, you say that you've already seen them and you were quite aware of those. Why not tell us? The best you can do for us is to say:
I have read these Super User questions:
- How do I do XYZ?
- XYZ: How does it work?
But I fail to understand this and that. Here's what I did … and I am
stuck here: …
This way we know that:
- you did your research
- you are aware that for you these are not duplicates
- we don't close them as such, because we know you've already seen them and you've told us why they're not
What should I do if I get a "possible duplicate of …" comment?
If you receive a comment with "possible duplicate of …", that means somebody voted to close your question as a duplicate of another. If you mention this user and explain why yours is not (see above), this will – in most cases – make sure it isn't closed.
If it gets closed and you still think it's not a duplicate, you should probably edit your original question according to the tips I gave you above, and then flag it for moderator attention, explaining your case.
You can also post it here on Meta and request for reopening. Always make your case and explain to us why it's not a duplicate, if you haven't already done so in the question itself.