For me, when I played Katawa, in the first playthrough, I'd usually play the game using my gut-feel. Any choice that I feel is the correct one, I choose it. Then, starting on the second playthrough to infinity, I will use "common sense" in choosing the decisions (Want character A's routes, choose choices that includes A in them). When I first played MuvLuv, I stupidly followed Amaterasu's "recommendation" to not play other characters' routes. What a big mistake that was.