How to write a rebuttal for a conference
Even for conference papers you can still perform (relatively small) changes after the notification. When trying to rebuttal, it makes much sense to address the main issues raised by the reviewer (and not to pick on the minor changes they suggest). Some good practices include:


Acknowledge good suggestions made by the reviewer. If those suggestions are easy to fix, say they are fixable and will be fixed in the final-version.
If the reviewers suggestion makes no sense or is not valid - explain why their review is invalid. However, you should acknowledge the fact that if the reviewers did not get it right, there might be a problem in your paper. Promise to clarify those issues for the final version.
If the review raise up a valid point that makes your result significantly weaker than you claim, I don't think there is a reason to rebuttal, but other might think differently (trying to justify why it is still a strong result).
Don't claim that the reviewer has no idea what s/he is talking about (even if that is indeed the case..)


Bottomline, you should be respectful and polite to the reviewers. Thank them for their suggestions and suggest to fix whatever is fixable even if you think nothing is wrong.