My advice, choose a topic carefully, study it, then come up with the structure of the paper before even writing a word of it. You can change it as you write of course, but I wouldn't advice eve starting a paper without knowing where you're going to.
Like GRR Martin often says when asked if he knows how his saga is going to end, "I know I'm leaving Chicago for Los Angeles, but I'm not completely sure yet if I'll visit Denver or Salt Lake City of both."