This is one question I just had to make.

So, you wanna to get a yandere of your own.

You'll want to reread through the guide, and make sure you know what kind of yandere you want.

For the basic or anykind of yandere. I recommend finding a girl that's a bit crazy, first, be her friend, and be a good friend. Slowly as time goes, get closer into her heart, and make her want to hang out with you.

You'll need to be romantic and even show signs of affection. Be sure to be romantic, otherwise, you'll end up with a yangire.

You got a yangire, but you want her to be a yandere. EASY!!! Try to move out of the friend zone, here are currently three ways.

-Hang out with other girls, and even show them the affection your yangire would've wanted from a guy they want. 
-Make them jealous in romance ways, if they get jealous of the girl that's asking for dates, remind your yangire, they put you in the friend zone.
-Be their best friend, and even treat them well, they'll start to think, that you're better as her boyfriend. 

Got a gf, but she's not a yandere? I'll help you turn her into a yandere.

Attempt to influence her to turning a bit crazy, and even make her jealous, but make it seem that you're not doing it on purpose. Watch yandere animes, or even play video games, and watch animes, or cartoon, that show a successful yandere, to influence her.

If you want a specific yandere, here is my advice for certain ones.

Possessive/Obsessive/
The Basic yanderes, no special work is needed that much

Cannibal
Cannibalism is legal, cannibals just need the other person's agreement, that ate their body part, with their permission. Just be careful, they snap, cops not gonna find your corpse. 

Hell
These yandere are highly rare, they're found in mental hospitals, or is that creepy girl in the back of the classroom, writing stuff in the desk with a knife. 

Incest
I doubt anyone wants these yandere, but oh well. Same basics for getting a yandere, or even turn the yangire into a yandere, but with your cousin, sister.........brother, mother, father, I don't really know, but the given info SHOULD work. 

Defensive/Protective/Assault/Assistant/Otaku/Medical/Intelligent/Sadistic/Religious/School/Stalker
Picky picky. For the first seven, find a normal person who are good with similar professions, a good grade of a topic that's similar to it, or is just good at it
For the mid three, find them in a certain place, for sadistic, go ahead and find the kind of store you would find them at, for Religious, go with a religious friend, and see if they can introduce you to any single ladies they know, i know you're not gonna want to say you're atheist, that might decrease your chance. School is kinda easy, if you attend school, then make a new friend, and begin what I taught you, if you're not, then contact a school friend, or attend a school that can teach you something you could be interested in.
For the last one, stalker, it's quite hard, without realizing it, your yandere could be stalking you as we speak. To get a yandere to stalk you, make a mystery of where you're going, or do whatever idea you got.

Double/Trio/Duelist 
Want to deal with one than one yandere? You have balls of steel, you'd make Chuck Norris and I proud.
It's very hard. One, you must have more than one admirer, and influence them to be yandere, or same with the old advice, find some crazy girls, and start the friend to boyfriend route. 

TsunYandere
One of the rarest yanderes, right next to the Hell yandere. You can actually find a yandere kinda easily. It can be someone, who gets jealous, and be more crazier than anyone in your neighborhood, and yet, always say, they're not in love with you. You'll need to pray to god, or play with luck, to find one.

Gun
So basically. Find a crazy girl who has the fondness with firearms. Who influence your badass firearm girlfriend, to being a bit over attached, yes, i know the bad things that can happen, and should do you.