It's always good to have your comic book appraised by a professional if you are looking to sell it. Comic Value would help you understand what you have in your comic book. There are specifications on how your comic book must look. The glossy cover and the brightly filled pages must still look as good as new or like they have never been read before, even if they have. In fact most people that keep the rare editions or collector's comics usually have two of the same comic. That means one was for reading and the other for safe keeping.
Most of the time you will find that the one for reading is different from the one that is all wrapped up in a clean sealed environment and kept in mint condition. This kind of time and conditioning that is given to the comic books can only be done by someone who loves comics and has the dedication to keep his or her comic book in the right conditions, atmosphere and surely knows the comic value. Such people get the comic book appraised and then put in time and money to make sure that the comic is in mint condition. Some of them even showcase their comic in conventions on these books and superheroes. The comic value goes even higher when more people get to view it and cannot get a hold of another copy anywhere.
It is important to make sure that you keep your comic away from any wet atmosphere or to keep it sealed tight in its case or plastic sleeve if you intend to keep it for a while. Also note that you must keep checking online for more news on how much your book is valued.