I used to write fan fiction, and I enjoyed it very much. There are, in fact, two of the stories I wrote during that time posted on this forum, so I can't take a terribly high road regarding this subject (though there are concerns about intellectual theft, copyright, and trademarks that should be a consideration and often are ignored). And there is some very good fan fiction out there. There is also some dreadful fan fiction being written. All in all, I think anyone who can write good fan fiction is capable of writing good fiction, period. After a year of writing fan fiction, I could write it no more. I was very conscious of stealing someone else's property (which bothers me as an idea) and of not pushing myself to be more original. As an exercise in stimulating myself to write, it was okay, but it didn't, ultimately prove very satisfying. Of course that's just me and I'm pretty much no one in the writing arena since I don't publish and, in truth, don't write very much these days. But if you are committed to fan fiction, ask yourself some questions...what if I didn't lean on someone else's beginnings to build my story...how liberating would that be? Should I be spending that energy and time on something I can never legitimately publish or on something that is truly my own? And you may protest and say, "But I'm not hurting anyone since I'm not selling it." But the person you may be hurting is yourself by putting yourself in a box of someone else's ideas. Just a thought, worth about 1 cent on the open market. And, as a postscript, I'll say that I saw one person who wrote brilliant fan fiction never push herself one step further and I know she could have written amazing novels and been published by now if she had taken that extra step. It wasn't something she wanted and now she's stopped writing. I think we lost an excellent author, and I'm rather sad about that. I could only stand to one side and be awed by her natural talent and saddened that she didn't have enough confidence in herself to go to the next level of originality. But, she did become a lawyer and I am sure she is equally wonderful at that. Perhaps some day she'll come back to writing and I will be there to buy her first book.