Light Yagami, from the Death Note anime and manga, is a formidable character and the reason why many want to be like him is obvious. However, although it is impossible to be exactly like him, it is possible to have him as an example to follow, and start to look more like him.
Steps

Step 1. Work on your appearance
The uniqueness of Light is that almost all the time he looks calm and peaceful. Choose a sophisticated style hairstyle. Also try to keep your face calm most of the time, not to look upset or particularly happy. Also, exercise physically and keep your body mass index (BMI) between 16.7 and 17.0. It is necessary that you do not go below 16.7 or go higher than 17.0, because if you do that, you will not be in good physical condition.

Step 2. Work on your personality
You will have to be able to constantly think about the smartest decisions (that is, the decision with which you will achieve the desired result). Never miss anything and forever try to be in control but without prove it (showing off or revealing that you are the leader is not good, because it attracts attention). If you pretend to be KIRA, you will also have to be capable of cheating. Get used to doing things that are morally wrong for the safety of the "common good." Also, don't feel guilty about your actions, even if it involves eliminating people *. They were obstacles. However, if you want to be only Light, you will have to be the exact opposite. You will not do anything morally wrong, for any reason. Take care of the people around you, even if you don't like them.

Step 3. Have pride
Although it may sound contradictory to step 2, you still have your pride. When the opportunity arises, go for victory. Also, never accept defeat. If you lose, be sure to plan a revenge. Of course, don't show that you are confused or upset, but be totally comfortable with anger. Take revenge later (secretly, of course, or in such a way that no one can find the link between you and your revenge, namely, an alibi). However, if you are going to be just Light, express your pride openly (never cheat or manipulate!) And perhaps, you can even become violent if someone dares to hurt your pride in a serious way (enough to make you understand; never try to hurt, just make things clear to the person you are talking to).

Step 4. Be smart
Remember how Light scored perfect on his To-Oh entrance exam? What about all the plans you made and did very well with? Your reasoning, knowledge and judgment must be in optimal condition and you must be able to know yourself and the people around you in an exceptional way. Predict the actions of others and yourself, whether in real or hypothetical situations. Increase your math skills and try to increase your charisma. Having a wide variety of talents at your disposal is also a very good thing. Also, train the mind; try to solve puzzles and play chess games (ie hack, Light can hack *).

Step 5. Go crazy
Light has his crazy moments (rather, Kira does, but you get the point). Learn how to create an incredibly creepy smile. You will also need to learn to grimace and chuckle without looking like an idiot. Let's face it, a lot of people who have a mean laugh look stupid when they do it, but Light doesn't. This is accompanied by his charisma. However, if you plan to be just Light and not KIRA, learn how to make your eyes shine. Charisma helps here too, but in a different way (and this has nothing to do with insanity, but persuasion, I'm putting this here so you can understand the difference between Light + KIRA and Light).

Step 6. Always have a plan
Light plans each move broadly, making sure there is no gap in the things he plans. It is always good to also have an alternative plan, in case the initial plan does not work.

Step 7. Feel safe, but be cautious
Do you remember the precautions Light took to know if someone had entered his room at some point or not? Even before he found the Death Note, Light still placed a piece of paper on the door frame and also placed a pencil lead on top of the door. And what about the handle trick? He is a genius. It may not seem like a big deal, but the truth is that it does. Take these kinds of precautions for whatever. This shows that you are always prepared, whatever happens.

Step 8. Be independent
Light will only depend on someone once he makes sure that he has manipulated that person enough to, in effect, trust them. We are all human and therefore we make mistakes. However, Light cannot afford that luxury.

Step 9. Try to be calm and reserved, but have the social skills to move in any circle
Also try to be light-hearted when around people, but make sure to give insightful comments. Above all, think before acting or expressing your thoughts.
Advice
- Eliminating does not necessarily mean killing, but getting rid of an obstacle. Killing is not okay. Don't do it, unless you really want to go to prison.
- Light hacks to gain knowledge, for constructive purposes and not for destructive purposes. Keep this in mind.
Warnings
- Don't hurt people unnecessarily; you will become the villain, not the hero.
- Light lives in a fictional world that doesn't look like ours. Please try to be more like Light and not KIRA.
- Odds are that your purpose in life is not to reset the world; Keep this in mind when you decide to look like Light.