http://www.mangago.me/read-manga/sayonara_heron/ ok...they're doing IT quite fast (though it's shounen ai so you won't see too much:P), but i like it for realistic plot
http://www.mangago.me/read-manga/double_line/
or i have slow developing love list:
http://www.mangago.me/home/mangalist/29342/?filter=&page=1 (no incest, only few high school love mangas,
I think those fit your criteria:
http://www.mangago.me/read-manga/sorenari_ni_shinken_nandesu/
http://www.mangago.me/read-manga/bikkuri_suru_hodo_doji_na_koi/ (very fluffy)
http://www.mangago.me/read-manga/boku_no_koe/ (first couple)
http://www.mangago.me/read-manga/hachimitsu_darling/

Yea so most of yaoi mangas, guys fall in love wif each other like it's totally normal nI feel I wanna see a (seme/uke) working hard to get his partner's heart!
-try not to give highschool
-I want them to fall in love wif each other first before they do it if possible
-nice if there's comedy
-no incest (stepbro/stepdad)
-pls be completed
-a manga dat makes u smile?
Srry for so many selfish request
If there are any genere which I listed on top, pls note me.
Thank you for helping me dear helpers! *hugs*