Tsukki and Yamaguchi aren't dating in the manga. The story mainly emphasizes their teamwork and friendship within the volleyball context rather than a romantic connection.
One of the well-known ones is 'Love Hina'. It has lots of funny and sweet moments in the dating scenarios. Also, 'Ouran High School Host Club' is another favorite, with unique and charming characters and their dating adventures.
Well, good character development is crucial. The characters need to be relatable and have interesting personalities. Also, a unique and engaging plot is a must. Maybe a bit of humor and some heartfelt moments too.