Yamato Nadeshiko Shichihenge♥, Watashi ga Motenai no wa Dou Kangaetemo Omaera ga Warui! Recommendations
Both feature socially awkward female leads who end up getting themselves into embarrassing situations. The difference is that, though both Tomoko and Sunako can't seem to handle being in social situations, Tomoko wants to be popular but fails miserably while Sunako wants to be left alone yet somehow manages to get a lot of attention. If Watamote left you unsatisfied then YNSH should provide more comfortable resolution.
Both have similar main character - girls who have antisocial character and their own weird intrests. Conversation is hard for them but they're trying to change something in funny way. Generally ambience of anime is similar.
Both series have a dark sense of humor, and feature a strong heroine that is considered a "creepy", "ugly", "outcast". These are very different yet somewhat similar with it's form of humor and it's dark shoujo theme about teen girls who haven't really found their true selves quite yet.