Aside from having "Academia" in their names, one notable similarity I noticed is how events are ordered. First, we have the main character enter an academy they have always been dreaming of entering. Next, they show us their school lives as they struggle through classes because of lacking something other students have. And then the plot starts and we see villain characters and how they are handled by the cast.
Do u have a dream? Do u have a wish to become as a great person who u admire?
Both show tell a story of a teenager who wants to be a Great hero/witch like their Idol in their childhood ...
They struggling, exercising, and hardworking to reach their dream, with their disabilities (Izuku from Boku no Hero Academia isn't have a quirk / any superpowers, when Akko from Little Witch Academia isn't has any magical power / isn't born from witch's bloodline)
Both have similar art style too, and very funny
Although these shows are very different in style and demographic, they share many similarities based on plot and characters. Both main characters try their best to achieve their dreams although they both have major disadvantages. Both series are about these characters overcoming this despite what everyone says.
An utterly stubborn main character aspires to become become a prodigy just like his/her idol despite having no talent and skills.
Each of their protagonists are fairly similar in their aspirations and how they start out. It's also fun to watch them grow and interact with everyone. Both series being visual eye-candy further adds to the experience!
An anime about a main character without potential have dreams out of their reach, they want to be the best at something they can't be. Guided by a mentor, who is also the person that inspired their dreams, and with the company of good friends, the main character fights with classes, villains and their own limits to reach their dreams.
At first they may look very different, but by watching just the first episode of both series the similarities in the story are noticible.
Boku no Hero Academia and Little Witch Academia (similar sounding titles) feature a young, teenager who's dream is to become something that most thought they couldn't be (Deku wants to be a hero, Akko wants to be a witch). They are teenagers who are surrounded by people gifted from birth with special powers, but they themselves lack the ability those around him/her have. They are inspired to want to be a hero/witch by a person who is the best at what
This seems to be so different but...:
Midoriya Izuku/Kagari Akko dreams of being hero/witch inspired by his/her idol, All Might/Shiny Chariot, but he/she can't because he has no quirk/she is not of a lineage of witches. Midoriya/Akko enters the academy that his/her idol studied but has problems adapting to have few skills, but is getting better with the course of the anime.
-Both animes are about an academy , in bocu no hero a hero academy and in little witch a witch academy
-In both the MC is weak and grows more powerful
-In both the MC have an idol , one of the best in their domain
They're both underdog stories, they're both kinda comedies, they both have great animation
Outside of the obvious "Academia" in their titles:
The animes have protagonists where they look forward to an idol of their lives, using them as an inspiration to their goals and coincidentally, they obtain some of their own powers for themselves.
Deku (my hero academia) has All Might, the #1 hero of the world as his idol and obtains his one for all quirk.
Kagari (Little witch academia) has Chariot as her idol, to the point of obtaining her wand for her own.