If you're looking for manga similar to Futakoi, you might like these titles.
Taiji Samurai, who enters a prestigious high school to find a girl who promised her future to him, dreamed of spending an ordinary high school life with her, but at the entrance ceremony that dream was broken...His father, the owner of Japan's No.1 giant cabaret chain, said that if a girl took his son's virginity, he would pay them 10 million yen.
The Momoru Club is full of odd people acting, well, oddly. The goal of the club it is reflected in its full name "The Liven Up The Moyama Shopping District Club." However, most members cannot do even the most basic of service related tasks. It is good that these characters act oddly. How else are they going to liven up the Moyama Shopping District?
How do you distinguish between the love from a cute neighborhood girl (who’s like a little sister to you), and the love from the hottest, yet quirky, girl in school? This is exactly the question Myung-Ho has to ponder when both his neighbor’s cute little daughter, Ji-Hae, and his school’s most popular diva, Yu-Ri, make him their valentines. Of course he cares for Ji-Hae, because the poor girl’s already been through so much for someone her age, but still, she’s only just a kid. Then there’s Yu-Ri, the girl of his dreams… or rather, she would be if she wasn’t a fortune-telling voodoo witch doctor. Oh and yes, it would also help if her father, the local gangster boss, wasn’t out to kill him. When you’re as lucky as Myung-Ho is choices are very hard to make.
Marriage Royale's story revolves around high school student named Tsukasa Hinomoto, who is told one day by his parents that he was adopted. Furthermore, they tell him that his real father is a manager of a large company, meaning he is very rich and holds a lot of power. Tsukasa's real father wants his son to marry a good woman, so he sets up an event known as Marriage Royale where beautiful girls from all over Japan will come together at a school built especially for the event and vie to become Tsukasa's fiancée. The school is located on an isolated island near Japan, and Tsukasa himself is taken there to live in a mansion in the care of two twin maids: Miku, the elder sister, and Miu, the younger sister.