In both manga living guy is pestered by a (shameless) ghost girl who loves him, but also loves to troll him. If you found that part interesting in one series, you might want to check the other one too.
Both Let's Fight Ghost and Tasogare Otome x Amnesia feature a boy who can see and touch ghosts and there is also this ghost-girl. However Let's Fight Ghost is royally messed up and you could say that the boy's relationship with the ghost-girl is umm... slightly different. Since both of those are comedy filled parodies of horror, you might like one of them if you liked the other.
Edit: Oh wait, Let's Fight Ghost completely stops being a comedy later on.
When thirteen-year-old Hajime goes to stay with his grandfather he gets lost and wanders into the Ark Cafe. There he meets Arashi, a sixteen-year-old girl with a big secret, and is immediately drawn to her. When a large private detective clad in camouflaged trousers and dark sunglasses walks into the cafe looking for Arashi, Hajime manages to help make him back off - for now. In thanks, Arashi goes to shake his hand but as she does so the pair connects and Arashi takes Hajime back in time to show him how the town used to look... while she was still alive! Now, after being ‘won' in a bet by the con artist currently managing the cafe, Hajime is working alongside the ‘ghostly' Arashi and fellow middle-schooler Jun who also suffered the same losing fate. As his life takes this unexpected turn, Hajime's stormy summer filled with student movies, moped races, and plenty of time travelling is only just beginning.
A boy meets a ghost girl and falls in love with her. The two of them (along with some other friends) spend their time solving mysteries, out of which the most important one is: why did the girl become a ghost in the first place?
What does all that have to do with Natsu no Arashi! and Tasogare Otome x Amnesia? Thats the basic plot of those two series. In other words, if you thought one of those series was interesting, you'll probably find the other one interesting too.
Pinocchio and Tasogare Otome x Amnesia have similar plot. Both of those series feature a bored ghost who has no recollection of his past life. Those also feature a person who can see the ghost. The ghost having finally found himself\herself a companion wants nothing more than to play around. In Pinocchio the ghost is a boy and the person whom he keps pestering is a girl, on the other hand in Tasogare Otome x Amnesia the ghost is a girl and the person whom she just can't leave alone is a boy. Both of those series mix romance with comedy, so even thought one is shoujo and the other is shounen, you might actually like one if you liked the other.
Chihiro is a macabre-loving high school student who collects horror films and thinks shacking up with a zombie chick would be hot. But though the idea of death is alluring, when faced with the actual death of his beloved pet cat, the teen buckles under the grief, and becomes determined to bring his deceased companion back to life. Every night, he sneaks off to an abandoned building and attempts to brew a resurrection potion, and it's here that he meets Rea, the beautiful daughter of the well-to-do Sanka family. However, the girl is having some troubles of her own, and after a mix-up ends up zombified herself! Now the horror fanatic is living the dream with his very own zombie girlfriend, but how will the pair deal with Rea's new diet and the onset of rigor mortis?
Both of these series are about a boy who has a close relationship with a dead girl ....who isn't all that dead. Both undead girls have a dark past. In Tasogare the girl's past is a huge mystery which dominates much of the manga. In Sankarea, the girl's past is made evident early on, but the big mystery is her future.