Accidental Athlete: Yamato Akitsuki, sort of. We as the audience don't see any initial signs of his athletic ability until he wins a race against one of the track team bigshots. But the characters later discover that he'd competed in athletic events in the past.
Cool Big Sis: Yuka. Sure she's a lush, but she's got no shortage of worldly advice for the youngsters.
Distant Finale: A mild example in the manga, which skipped over a year between the last two chapters, between Yamato and Suzuka getting legally married by turning in a form in chapter 165, and having a church ceremony a year later in 166 after they'd saved up enough money
Dub-Induced Plot Hole: Minor, but worth mentioning. During the dubbing process, someone apparently overlooked the order-of-magnitude difference between tenths and hundredths of a second, which of course is Serious Business in the world of track. Luckily this only happens a few times. But at one point after Yamato runs a race in 10.68 seconds, the dub gives his rival's time as "eleven point nine" (11.9) seconds where the real time is 11.09 seconds. This gives the false impression of a much larger gap between the two runners.
Everyone Can See It: Suzuka's probably the only one who didn't see Yamato's initial interest in her. Once Honoka moved in on Yamato and took his attention away, then suddenly it was only Yamato who couldn't see Suzuka's newly-developed (and oft-denied) interest in him.
Lethal Chef: Suzuka is a low-key one who does things like boiling eggs in the microwave (creating what Yamato sometimes calls "egg bombs"). She gets better. Yui, who works at a cafe, is... much worse. Her vegetable soup, for example, has a fish head staring out of it. For a "hidden taste." She never notices anything wrong.
Loving a Shadow: Early on, Suzuka's only interest in Yamato seems based entirely upon his resemblance to her dead not-quite-boyfriend/sempai, down to the way they set up to run a race. Made more dramatic that the said semapi was going to confess his feelings towards her on the day of a track tournament, which was also the day he died. She got better though, saying goodbye to her late sempai at his grave and moving on to Yamato.
Stalker with a Crush: Yes, Yamato, it still counts as stalking if you're listening through your own door to hear Suzuka leaving her apartment.
Chapter 95 of the manga focuses on Miho's (Yamato's cousin) classmate who is very stalkerish towards her, especially on Valentines Day. He's like an extremely creepy Deconstruction of Yamato's own early Dogged Nice Guy behavior towards Suzuka (minus the "nice"), and even resembles Yamato a little.
Stripperiffic: Miki's "sprinter outfit," which resembles a bra-and-panties ensemble, or rather, more appropriate for beach volleyball than track and field. It's not necessarily impractical for running, but it's worth pointing out that no other female on the track team dresses that way.
Amazingly enough its a case of Truth in Television. If you actually see an international track and field event one or two of the female sprinters are usually dressed like that, the rest are slightly more covered up with shorts and longer shirts.
Title Drop: Obviously the mention of Suzuka as a character doesn't count, but the final episode's title uses the same kanji characters as Suzuka's name and the series title, only with a different reading.
She's much more relaxed by the end of the manga, though it may very well be the pressure of a sudden pregnancy and having to drop their college plans to raise the child. An Omake in Kimi No Iru Machi, another work by the same mangaka, shows Suzuka and Yamato together two years on, and they're arguing about the proper shape for mochi (a sort of rice cake made of rice pounded into a paste and then molded) when put into zoni soup, a traditional New Year's dish.
Unknown Rival: Inverted: Yamato actually becomes one of these for awhile when he picks a fight with a star athlete from another school.