Will there be any problem for me or any action will be taken against that topic.
Only admins/mods can see who report the post so you don't have to worry about getting any issues from those that wrote the posts/topics you reported. Regarding any action taken, if report is valid posts will be removed, as simple as that. Also, don't fret about having bad reports, we all get it from time to time.
If you are unsure, and until you gain more experience, you can ask the community for an opinion. Post here (or better yet, open a new topic in the Meta board) with a concrete example that you believe violates the forum rules. Getting feedback from more experienced members will help you to know how to report to moderators better.
In my opinion, best place to ask for help or opinion is
Spambusters thread. At least that's the one I used when I was starting with reporting, and I am still use it occasionally.