I will explain to you very quickly in this guide how to play Chibi Yandere Complete Edition with a focus on Socializing and Reputation.
At the begin of the game, everyone is neutral toward you. You have 50 Reputation and 50 opinion with everyone. Your first goal is to socialize with your classmates.of the Classroom 2-1. They will stay the same even if you start a new game. Use the students list to table to check those informations rather quickly.

The people of your classroom are as follow:

• Sakura Hagiwara (Gardening club)
• Daku Atsu (Occult club)
• Hayato Haruki (No club)
• Juku Ren (Martial arts club)
• Koharu Hinata (Cooking club)
• Mina Rai (Martial arts club)
• Osana Najimi (No club)
• Riku Soma (Drama club)
• Yaku Zaishi (Science club)
• Yui Rio (Cooking club)
• Sukubi Dubidu (Photography club)
• Tokuko Kitagawa (Drama club)

Focus social interactions with those students during the first week and try to get friends with most of them. I will explain later in this guide how to to optimize opinion for those students.

As you noticed, you should join the following clubs to increase your relationship with those students:

• Cooking Club, you have two classmates in this club and you'll gain access to the feed option that you will be able to use if you're lucky.

• Drama Club, you have two classmates in this club and you'll earn reputation and money in the long run.
• Photography Club, only one classmate is in this club but you'll have access to more quest in the future.

For your studies, you should focus mainly in Social science and a bit in Language.I will explain later why.
At the start of the game, you'll get an easier time with the following homeroom teachers:

• Karina Hana (+1 additionalSocial science for each study points)
• Ni Kanwa (+1 Opinion for each social interactions)

This out of the way, let's begin with the key actions when beginning the game.

1. Complete Osana's quest
   

This one will help you quite a lot to be friend with the rival and eliminate her peacefully. Go to the main fountain of Akademi High School. Osana will be here during the morning and the lunch break.

You'll find right next to her Senpai, avoid getting too noticed by him or you'll loose the game. Interact with Osana with the Confirm key (spacebar) and she'll ask you to help her out. Obviously accept to help her. The quest of Osana's will normally be active. You'll just to need to save Lucifur (her cat) from a weirdo. You must go to Hana District. If you're lost, you can always check the map by pressing the M key. You can take your time to explore the city and complete the quest of the mayor (collecting the trash and disposing of them). By completing the mayor quest, you'll get the title "Friends of the mayor". It's not just honorific, you'll get free access to bus. Using the bus will instantly teleport you to the designated location for the cost of only one minute. Quite nice for saving stamina and money. Don't forget the +3 Reputation and free poster that you can sell to the Pawn shop. It will be usefull for the begin of the game since you'll not have a lot of opportunities to increase your reputation.
As the mayor of Buraza town always says: "If you don't pay for it, someone else will pay it for you."
Ah... Classic Doradu Turempu... 
Let's return to the topic, you finally decide to go to Hana. Normally an arrow will appear helping you to notice the house you need to go. Interact with the arrow by pressing the confirm key.

You'll enter to the house of the weirdo, just interact with the cat without being noticed by the four eyes guy.

When you have the cat, return to the window and interact with it by pressing the confirm. Don't be noticed by the nerd. If you fail, you'll be able to retry. Don't worry, it's quite easy to complete. If you're outside the house, you'll just need to go to Osana's house which is located close to your house. Check the map and enter, an event will occur (unless you did something bad to Osana) giving you +10 Opinion with  Osana.

2. Be friend with Osana

Your next goal is to be friend with Osana before the end of the week. To increase your chance you'll need to buy her student profile in This is the icon you're looking for)

It will cost you 1000 yens or 500 yens if you're in the Photography club. Check the Icon in the Saikouphone. Do you have 

You can obtain student profiles for free by becoming friend with another student.

You'll need more than 80 Opinion to be friend or 60 with the Pink panties equipped. (Available at the Uniqao store with no requirement for 2100 yens or at the pawn shop for 1890 yens. You can also use the Black panties to get +1 Opinion for each social interactions. You can find it with no requirements at the pawn shop for 2250 yens or at the Uniqao store after reading the manga Chibi Momoko Chan for 2500 yens. Chibi Momoko Chan will cost you 400 yens at the book store and 360 yens at the pawn shop. Don't forget to sell the mangas you've done reading at the pawn shop for cash back (10% of the normal price).

You should focus your routine on studying and interacting with students. Social science is the key subject to study, by increasing it you'll increase the number of social interactions per day. That means more opinion gained during the day. Study also a bit of Language to unlock new mangas.

When having the student profile, youl'l have important details of what the characters likes and dislikes, use this information to your benefit by interacting with the character and choosing the subjects he or she likes. You will be able to use the Compliment interaction to increase your opinion when having done all benefitial topics. If you're in the Cooking club and have cookies, you can use them to also increase their opinion.

When you'll have more than 60 Social science and be friend with Osana to unlock the interaction "Ask the rival to reject Senpai".
The probability of success will depend on the following parameters:

In your favor: Opinion below 80 and your social science stat.
Against you: Police alert level, School Atmosphere, Social science of the rival.
Osana have 62 in Social science, you'll have at least 60. In the last version you'll have at least 68% to get reject Senpai. (The current version is minimum 84%) This is the easiest way to get rid of your rival in the first week.

3. Increase your chance to become student council

As seen in the previous post. You'll need to focus on your  Social sciences statistics and Language statistics.
You also need to focus social interactions with your class mates. You need to increase your reputation or at least try to maintain it.

To help you, you should read Viper manga (available at the pawn shop 1800 yens or at the Book store when you have more than 80 in Language.

Reading this manga give you the trait "Charismatic" increasing your chance to get chosen by your classmates.

How classmates will pick you or someone else?

Here is the formula:

For you: Reputation+Current Opinion+the Charismatic Bonus

For opponents: Reputation*2+the Charismatic Bonus

Your goal is clear here, you need to have opponents with the lowest Reputation. It's randomize, if you're not lucky maybe avoid wasting your time and focus on other parts of the game and saving some bucks. Luckily, your classmates don't have very high reputation.

Here is the three most difficult students:

• Sukubi Dubidu
• Riku Soma
• Koharu Hinata

In the easier side you'll have:

• Daku Atsu
• Juku Ren
• Yaku Zaishi

Important, you must be at class during day 3 to participate at the elections. Check your calendar to see upcoming events.

The next you'll have the elections (and the results) and your first meeting as student council.

Note that you will be able in the long run to avoid bad proposals that are always against your profit . It will increase your reputation and will allow you to play more risky. The benefits are quite game changing but other ways to play may give you a huge lead. I will upload other strategies and explain them in detail. Maybe being hypocrites is not your thing, you want to be wild and don't care about consequences. Maybe you want to be a bit more sneaky and killing people without being noticed by the police with the "perfect crime". We will see more way to play and to win the game.