If you're looking for manga similar to Akiiro Bousou Biyori, you might like these titles. All recommendations are made by Anime-Planet users like you!
Both are really short one shots, written and drawn by the same author. Each is about a girl and a boy in a semi-romantic situation. Akiiro is far more ecchi, with a lot of panty shots and some nudity as well.
They're both also drawn in full colour, and generally have a pretty good standard of artwork in them.