If you liked the K-On! anime, the Anime-Planet community thinks you'd like:
Everyday life may be full of mundane occurrences, but hidden amongst the banality, you can always find something fun to brighten your day. While schoolgirl Mio attempts to cheer up Yuuko after her horrific test score, Nano desperately tries in vain to get the stubborn Hakase to take her medicine. No matter the situation, these innocent girls can make the most of every situation, even by doing cartwheels at a deserted railway station.
Ouran High is a school for the extremely wealthy or, in Haruhi's case, the extremely talented. But no amount of talent will help when Haruhi accidentally drops an eight million yen vase in a music room. The vase was the property of Ouran High School Host Club, a group of attractive young men who, for a fee, provide their time and affections for their lovesick clientele: the female students. Fascinated by this strange new specimen, a poor and clumsy commoner, they force Haruhi to work for them until the debt is repaid; but they get a lot more than they bargained for...
Both OHSHC and K-On! are lighthearted series featuring high school clubs, and they both have plenty of comedic moments.
The characters are lovable in both series, and although there are differences between them (more of a romance element in Ouran than K-On!, different main character sexes), but they both have themes of friendship and school life.. and they're both super cute! ^.^
She’s smart, talented, and the newest teacher at Momotsuki Academy; but she’s also… 11 years old?! Named Becky Miyamoto, this pint-sized MIT prodigy wants nothing more than to be a respectable educator, but all her students do is treat her like an adorable child! With space aliens, a class full of stereotypes (and one girl who is normal!), and a quick temper standing in her way, Becky will try her best to shape the eager young minds of tomorrow before she hits puberty!
Both of these have a very laid-back feel to them and are focussed around some girls at high school and what there daily lives are like. I'd say K-On! has more of a natural feel to it and Paniponi Dash is more eccentric but both are very similar.
When Sasami was very young she promised her parents that she wouldn't use her magical powers - though as a young girl, she sometimes does an innocent deed regardless. Sasami always has a positive attitude and likes making new friends such as the timid Misao, and loves to cook. However, when the Cooking Club's leader - the new teacher Ms. Washu - seems insistent on making the girls prove their worth, they soon discover that the club is just a front for the Magical Girls Club! It seems that Ms. Washu is actually here to make sure any magic-using girls use their powers responsibly. Along with Misao, Makoto, the rabbit-like Ryo-Ohki and other new friends, Sasami trains hard to be the best Magical Girl she can be!
Sasami: Magical Girls Club and K-On! share quite a few similarities. In both shows, there's an after-school club that the characters participate in that brings them closer together; these after-school clubs are a source of learning, humor and chaos for the girls, and both shows follow the adventures of the main characters in their clubs. K-On! is about music and is more realistic while both seasons of Sasami: Magical Girls Club have fantasy elements to them, but both shows have cute girls building strong friendships with each other. If you liked the characters and their relationships in one show, I think you'll like the other!