Plot/Story
There isn't exactly a "plot" in Azumanga Daioh. Basically, it just follows the school life of normal (or less than normal) high school girls. Sakaki keeps having bad luck with cats. Chiyo continuously earns excellent grades. Osaka is always dimwitted. Yomi is perpetually annoyed by the energetic Tomo. This is what usually happens.

Characters
The characters are very enjoyable. They are each unique in their own ways.

Mihama Chiyo- Mihama Chiyo is a cute ten-year old student that skipped five grades to go all the way to tenth grade. Not only is she incredibly cute and smart, Chiyo is also very rich. However, Chiyo is not snobby or spoiled, rather nice and caring. Chiyo is the Class Representative for her class as she is smart and responsible. Chiyo is good at cooking. Chiyo is very short, even for her age. Tadakichi-san, her dog, is bigger than her. She longs to be tall, like Sakaki. Chiyo is also horrible at sports, even for her age.

Kasuga Ayumu a.k.a. Osaka- Kasuga Ayumu is a transfer student from Osaka. Tomo, who thought Ayumu would be a loud, annoying student fond of lame jokes, named her Osaka immediately, much to Kasuga's discontent. Osaka is a somewhat dimwitted person, but does seem to know a lot about certain subjects. Osaka is very childlike, always curious about things. She also has many supernatural dreams about Chiyo's pigtails. Osaka believes that what happens in these dreams can happen in real life. Osaka, like Chiyo, is horrible at sports, but even worse than Chiyo. She is part of the Bonkuras, a group consisting of her Tomo and Kagura, the stupidest in the class.

Sakaki- Sakaki is a tall Japanese high school girl, at 174 cm and is still growing. Her breasts are very large too. Because of this, Osaka has once called Sakaki an American. Sakaki is very fond of cute things, especially cats. Almost everything she owns is related to cats. The only thing that she doesn't own that is cat-related is probably a cat. This is due to the fact that her mother is allergic to cats. Although she loves cats, Sakaki's luck with cats is horrible, either getting bitten by the cats and the cats run away when she tries to touch them. Many people seem to "like" her. This includes girls too. Sakaki obtains a cat later on and plans on living with it during her college years. Sakaki believes that Chiyo's dad is a floating cat-like figure know as Chiyo-chichi. Although she doesn't like sports, Sakaki is very athletic.

Takino Tomo- Tomo is a wild, energetic character. She is somewhat annoying. Tomo is part of the Bonkuras, a group consisting of her, Osaka, and Kagura. Tomo left the group because she thought she wasn't stupid. When she tries, Tomo seems to be able to do well, which is the reason why she was accepted into the high school she is in, although how Osaka and Kagura were accepted is unknown. Tomo often dreams about being better than Sakaki at sports and being smarter than Chiyo in academics. Tomo wants to become an ICPO, despite the fact that she has no idea how to become one. Tomo is the Assistant Class Representative.

Mizuhara Koyomi a.k.a. Yomi- Koyomi, or Yomi by basically everyone, is a serious high school girl. She is often irritated by Tomo. She and Tomo have been classmates since elementary school. When she is annoyed to a certain extent, she will start fighting with Tomo or even hit her with a one-hit KO punch. Yomi is good at both sports and academics. Yomi loves eating, but she continuously tries to find ways to lose weight, despite that she isn't really obese. Although serious, Yomi may occasionally play pranks on people for fun. Yomi is horrible at singing.

Kagura- Kagura is a tanned high school girl who is fabulous at sports. During her first year, she is not in Yukari's class, but she is later transferred to Yukari's class so that their class can have a better advantage in winning the Athletics Festival. Kagura loves sports, especially swimming. Kagura is in the swimming club. Along with Tomo and Osaka, she is part of the Bonkuras. Kagura once lost to Sakaki in the Athletics Festival and since then, she desires to become friends and rivals with Sakaki.

Tanizaki Yukari- The homeroom teacher to Class 3 and the English teacher, Yukari is called Yukari-sensei by her students. She is violent, selfish, and lazy. Due to certain circumstances, Yukari may hit other people if they anger her. Although she loves to look at food she can't afford, she will get mad at people and hit them if they have eaten them before. Yukari is a horrible driver. While she's driving, anything in her path will be annihilated.

Kurosawa Minamo a.k.a. Nyamo- Nyamo is what Yukari calls her friend (or not) Minamo. Nyamo is the homeroom teacher of Class 5 for the first year and Class 2 for the next two years. Yukari often says Nyamo is a dumb P.E. teacher. Yukari freeloads from Nyamo. Nyamo is very nice, unlike Yukari, and is loved by her students, getting great presents from her students and being respected by them, which causes Yukari to become very jealous. Nyamo seems to have several past relationships, but none of them worked out, which causes Yukari to tease Nyamo, which makes her very mad.

Drawing Style
The drawing style is very good. Each character's appearance is very unique. In particular, Chiyo is very cute, and so are a couple other characters in Azumanga Daioh.

Enjoyment
Azumanga Daioh is a very enjoyable anime/manga. The comedy is great. The characters are great. Everything's great. It can be read or watched several times.

Overall
Azumanga Daioh is definitely an anime/manga to watch/read. Each episode/chapter will make you laugh as it did to me. It is very interesting. Nothing is too grand or too huge. It's just basic and humorous.