こんにちは! From April to August of 2018 I was lucky enough to live and study in Osaka, Japan. I participated in the Lab Research, Engineering and Science program at Osaka University. During the 5 months I was a full time research student studying biochemical engineering.
My family and I left for Japan at the end of March, so we got to there during the last few days of the hanami (はなみ、花見) season. The sakura (さくら、桜) petals falling everywhere was such a beautiful sight to see (10/10 recommend going if you can).
My sister and I both play Pokémon Go (because gotta catch them all ya know) and have loved Pokémon since we were younger, so of course we had to visit the Pokémon Center. When you walk in there are lil statues of different Pokémon, a wall of Pokémon games and gacha toys, and of course a whole bunch of plush toys!
The main tourist attractions of Osaka (in my opinion) are Osaka Castle, Umeda Sky Building, and Dotonburi. My family decided to visit Osaka Castle while we were wearing kimonos (きもの、着物). There are several different stores where you can rent kimonos for a day for different prices. It might be better to make reservations, especially if you're going during a popular time (i.e. cherry blossoms or summer festivals). The store we rented our kimono from allowed us to choose the different colored layers, a cute lil handbag, and a hair accessory. They also offered to pin up girls hair for an extra fee. Although we didn't go inside of Osaka Castle, the outside was still very beautiful. (I'm not too sure but I think you can go inside for a certain price.)
Umeda Sky Building and Dotonburi I feel are both sights to see at night. The Sky Building had a great 360 view of Osaka. The entrance fee was ¥1000 (about $10). If you wanna go at night, it might be better to go up to the observertory about an hour before sunset because when I went there were a bunch of people waiting for the sunset as well. Dotonburi is a great way to experience the night life of Osaka. There are giant statues of different food sold (such as crab and blowfish). And of course there are always people posing in front of the Glico running man. There is also a river cruise you can take, which the tour guides talk about the Dotonburi area.