(I got the first 2-5 paragraphs from SOS with some editing.)
She seems to come from a well off family. She definately doesn't seem poor, afterall Juuban is a relatively rich district, which is where she used to live and where the story Bishoujo Senshi Sailormoon is mainly set.
Takeuchi-sensei liked drawing manga since she was young. She was in the drawing club in high school, and often drew manga. Her first official manga was at 18. She started contributing to Nakayoshi while in high school.
In 1986, while she was attending Kyoritsu Yakka (pharmacy) University, she made her debut as mangaka with "Love Call" which received "Nakayoshi New mangaka award." It was published in "Nakayoshi Deluxe" September 1986 issue.
After graduation, she took a job as pharmacist at Keio Hospital. She is a licensed pharmacist (though she admitted that she's a little rusty ^^;;). She says she still loved drawing manga but since she worked hard to earn her degree, she wanted to try that, too.
Although she was working full time, her editor (Not Osa-P back then.) continued to encourage Naoko-sensei to draw manga.
Eventually Osa-P came to edit, and together they created a lot of the manga that we know, including "The Cherry Project" After completing the series, Takeuchi-sensei wanted to do "fighting magical girls for love and justice. Osa-P asked her to do them in Sailor suits. Thus, "Codename wa Sailor V" was created. (starting with vol. 3)
"Codename wa Sailor V" was so popular that Toei wanted to make it into an anime. Kodansha and Toei struck a deal with Takeuchi to create the manga simutaneously with the anime (with the key parts of the anime coming first). The anime was to be called, "Bishoujo Senshi Sailor V", but she and Osa-P decided to model the anime on the five soldier action figures that's common in Japan. So she recreated the show, with a new heroine, Sailormoon, and then decided to make her the leader. She created "Bishoujo Senshi Sailormoon" (starting with the act where Sailor V Shows up).
However, she did not give up the serialization of Sailor V, and continued it even after Sailormoon was done. (She did it on and off)
Sailormoon was then run in the Nakayoshi Febuary 1992 issue. That was popular too, so they started the anime of Sailor Moon which debuted March 7, 1992. The anime was very popular and was sent to foriegn countries.
She has since then been collecting Sailor Moon Merchandise, and antiques. (Her favorite anime is Sailor Moon, of course, and no one in the entire world can claim that they are a bigger fan than she is. ^_^) She has called herself an old lady (adorned with *sniff*s), and a Princess, the latter is a nickname between Togashi-sensei and herself! (They are a really cute couple!)
She left Kodansha after they lost 7 pages of her original manuscript for her PQ Angels!, which she wanted to put out in tankoubon. But then she reconciled with Kodansha later, just enough to get them to print The Materials Collection (which was one of the other reasons she left). She also printed the Infinity Art Collection book, which is more od a memorial to Sailormoon.
She is now currently married and making manga so she can fuel her antiques hobby. She has a new boss now that isn't Osa-P (who she said left for another magazine).
She published "Hime to Ouji no Baby Punch!!" in Shueisha and is enjoying her leisurely life of only occasionally drawing a manga, and has now found a love of gardening. Kodansha is still trying to get her to return to Kodansha, but she seems reluctant (afterall, they did lose her manuscripts, and didn't let her search for them.. threatened to not let her publish the Materials Collection.. and didn't give her her fan letters..). She doesn't seem to have a contract with Shueisha and is simply freelancing, and helping her husband with Hunter X Hunter.