This one pretty good imo
http://www.mangago.me/read-manga/unchanging_days/tr/90730/page/
http://www.mangago.me/read-manga/watashi_baka/
http://www.mangago.me/read-manga/aoi_honoo_kaoru_tsuchi/
And anything by this mangaka ↓
http://www.mangago.me/read-manga/parfum/
Mars Kiss!!!!!!!!! It's great!
Haven't read that many shoujo ai. So, i am just gonna recommend you the ones I read & found adorable -
http://www.mangago.me/read-manga/tamen_di_gushi/
http://www.mangago.me/read-manga/magandanai/
http://www.mangago.me/read-manga/exciting_feelings/
they are all webcomics though.
I was looking through my MAL account, and I clicked on the shoujo ai category. I noticed that the highest rating for a shoujo ai manga I had was a 7. The rest were all lower. There really aren't a lot of shoujo ai options, and from the ones that exist there aren't a whole lot of well written ones. I'd appreciate if anyone were able to give me some recommendations.