I don t know what to do

Hi I m traveling with my best friend for 7 days to Japan , we are planning to see the cherry blossom festival and eat the amazing food they have in japan, we don't have any other ideas what else we can do but will be in Shingiku for 3 days 4/5 to 4/8
Roppongi for 2 days 4/8 to 4/10
Ginza for 2 days 4/8 to 4/12
Can you give us some great suggestions on what to do in this cities?
we were thinking to also visit another city for a day as our hotel is in Tokyo ,any suggestion for an amazing city near Tokyo?? Thank you so much
Oana