I read Medalist and liked it a lot. It's the sort of well made manga that makes me come back to the medium even though I have by now essentially grown out of anime. I find the trainer, the girl, and their relationship as a well made and interesting foundation for the story, but it is the rival and her orbit that captures me; they make a great dynamic together.
If you have not read them, then Ran to Haiiro no Sekai, The Magnificent Grand Scene, and my beloved Narutaru would be good recommendations in a similar vein. Now, "little girls and their coming of age" is hardly my favorite subject, but all of these are really solid. Fair warning though: Grand Scence hasn't been translated for I believe soon to be two years and Narutaru can be somewhat heavy.