To be the greatest detective of them all and save the world, you need to base all of your assumptions off of the findings of dead people. Hey, they're dead, nobody will know that evidence isn't yours—you can be a hero!
Another Note: Hide out in your safe house and have the Fair Cop you've recruited do all the work and then claim credit for solving the case when it's through. If you are the law no one can question you.
Extension: Women are weak, incompetent and need a man to lead them (and even then they are prone to making mistakes). Once they find him, they should Stay in the Kitchen.
If you've fallen in love with someone naturally the appropriate response is to stalk that person, have your crazy friend threaten to kill him, and dress like a whore. Your victim (I'm sorry, BOYFRIEND) will grow to love you eventually.
ALL PROBLEMS ARE SOLVED WITH HANDCUFFS. If it isn't working, the handcuffs aren't small enough.
Never mind if your ideals are completely correct—if you develop a God complex, you must die and your work must be undone. You just wanted to make the world a better place and had to make some insignificant-in-the-grand-scheme-of-things sacrifices? Sorry, you're not a nice person, so you lose.
Writing in books is dangerous and evil. It's not a pretty picture. (Dramatic and stylalized, perhaps, but not pretty.) Don't do it. Ever.
Mass-murder is AWESOME!!! There is NOTHING it cannot do. Start slaughtering people today and you too can have a hotgirlfriend, steady job, legions of devoted followers, and (drumroll please) . . . world peace! Even if you die! That's right, kids, utopia can be yours, just make sure you start out by bumping off criminals . . . that way, you'll be justified no matter how much of a monster you become. Everything you say and do is right! Just remember these three simple rules: 1) if you think they deserve to die, they deserve to die, 2) if they get in your way, they deserve to die, and 3) if the world isn't a utopia yet, that just means you haven't killed enough people! Act now! Utopia is just a drawn out mass-murder session killing away!
The only thing more epic than writing in a notebook . . . is eating potato chips. Unless you repeatedly shout "delete" whilst writing in said notebook, then the sheer epic-ness might just make you come to fruition.
Matsuda is an idiot.
Do nothing. Don't ever try to change the world for the better. Sit around in your room and play with toys all day and you are sure to win at life.
If your little sister is ever kidnapped by violent criminals kill her immediately because if you save her it will lead to your death.