If you liked
Kimi ga Koi ni Ochiru
|
...then you might like
Empty Heart: Itsuwari no Koi Dakara
|
Both stories start out with a younger brother, his elder brother, and said elder brother's good friend. The younger brother is in love with the friend, who is in love with the elder brother, but sees no chance for himself; the younger brother takes advantage of this and seduces the friend, who eventually falls in love with the younger brother instead. The main difference between the two stories (apart from the fact that the seme and uke roles are reversed) is the elder brother's reaction. In one, he is merely the protective elder brother, oblivious to his friend's feelings for him, while in the other, he is revealed to have actually been in love with his friend as well.
If you liked
Lovely★Complex
|
...then you might like
Kimi ni Todoke
|
Both are light-hearted comedies about a pair falling in love. Potential "rivals" do appear, but as the main pairing shows little interest in these other potential romantic interests, there is not much in the way of the typical "love triangle" development (a BIG plus in my book). Instead, the stories tend to focus on the development of feelings between the main characters, and the misunderstandings between them that they overcome.
If you liked
Kimi ga Koi ni Ochiru
|
...then you might like
Rin!
|
Both stories are romances between boys that takes place in a kyudo (Japanese archery) setting. Rin! is about a boy and his elder brother's best friend figuring out that they are in love and finding their way in the beginning of a romantic relationship; Kimi ga Koi ni Ochiru is about a boy who is in love with an old friend of his elder brother's, who is in love with his elder brother.
If you liked
Empty Heart: Itsuwari no Koi Dakara
|
...then you might like
Kusatta Kyoushi no Houteishiki
|
Both series contain a character who starts out in love with someone, but ultimately ends up falling for that someone's younger brother. They also both take place in high school, where the main pairing is a student and a teacher. Kusatta Kyoushi no Houteishiki is longer, and more oriented towards the emotional aspect of the relationship--there is little physical intimacy between the main pairing until the last two of ten volumes; Empty Heart, on the other hand, has the main pairing jumping straight into the "physical" and only sorting out the "emotional" at the end of the story.
If you liked
Junjou Romantica
|
...then you might like
Empty Heart: Itsuwari no Koi Dakara
|
The Romantica pair of Junjo Romantica have a similar sort of beginning to Empty Heart--a main character is in love with his best friend for years, but said best friend doesn't notice and goes on to get married; he then ends up sleeping with said best friend's younger brother and falls in love. The characters themselves, however, have very different personalities, so the relationship dynamic is somewhat different in each story.
If you liked
Empty Heart: Itsuwari no Koi Dakara
|
...then you might like
Rin!
|
Both stories revolve around the main character falling in love with his elder brother's best friend. However, Empty Heart contains more angst, since the elder brother's best friend is in love with the elder brother to begin with; Rin! is a little more light-hearted, being more oriented towards the main pair innocently discovering how much they mean to each other.