Makoto (or Lita) is an orphan who lives on her own as her parents were killed in an airplane crash. As a result, in the manga, she hides behind her curtains when one flies overhead. :) Makoto appears after Rei is found as a transfer student to Juuban Junior High (like Ami) because of troubles at her old school. Attracted by her bento, Usagi befriends Makoto, disregarding the horror of Naru and Umino, and the third of the inner senshi was found. =)
Makoto's personality is rather contradictory. She is physically strong, and a fighter (typically "tomboyish" qualities), yet she is the most "housewifely" of the senshi, cooking and cleaning with much zeal. Makoto also is very romantic, believing that everyone she's attracted to looks like her old boyfriend.
She seems rather overlooked in the series, though.
Anyway, as Sailorjupiter, Makoto utilizes forces of lightning, and wood as well as employing her physical fighting too. She is an aggressive fighter, and probably about as powerful as Sailormars (but that's just my opinion ;)
(And, like most of the characters, Makoto is rather prettier in the manga than in the anime.)

Minako (Mina) has a sunny, super-cheerful (according to Naoko :), and ditzy personality. She is the last of the inner senshi to appear, and she finds them rather than being found. Minako is one of the more powerful inners, and the most experienced as she previously lived in England fighting solo as SailorV with her cat advisor, Artemis. (In the last act of SailorV, she feels something calling her to Japan, and so she packs up and leaves :)
Minako's personality is... like Usagi's. (Takeuchi Naoko has said that Usagi is based upon her, although SailorV was created first, so one can assume that both are based upon her personality.) The episodes that focus on her are very, very humorous as she tries to nurse the senshi back to health, proves that her heart is pure enough to have her crystal stolen ^^, stalks Haruka with Usagi (they mirror each other's behavior perfectly :), and chases idol stars in general.
Sailorvenus uses attacks that deal with love and light sort of things. She is more focused and less ditzy in battle, and more competent than Sailormoon in the beginning series. In the manga, Sailorvenus is the true leader of the sailor senshi, though in the anime, they didn't preserve her position. They also made her rather less mature...and consequently very funny^^.