@EllaPaella where's your denim jacket from? I've been admiring it for ages!
@faffadoodledo Ah please accept my apologies in advance if my message gets too long, I always get a bit enthusiastic with this subject.
I’d definitely recommend avoiding summer at all costs! Winter is okay, but spring and autumn are the best in terms of temperature, weather & seasonal beauty (I’m speaking about Tokyo here).
I’d personally recommend visiting during sakura blossom season tbh as it’s really something special. I know some people choose to come during autumn foliage season to see red maples, but after living here 10 years I feel that the best timing to see the leaves varies too much each year to predict anything (while with sakura you’d be sure to see beautiful blossoms if you visit around 1-2-3 of April) and you’d need to go to parks with maple trees specifically to enjoy the foliage (while sakura blossoms all around the city, you’d see it everywhere you go).
You won’t be disappointed by local food and service and there will be lots of fun places to visit for people of all ages. From Disneyland/ Totoro/ Moomin/ Harry Potter themed parks to temples and museums (I’d strongly recommend visiting digital art museums). Speaking of temples, many tourists love to go to Asakusa (probably the most famous temple in Tokyo), rent kimono and get traditional hairstyle done in one of the many shops around there and then stroll ancient streets while eating traditional Japanese sweets. You can also purchase an amulet at a temple and a fortune slip. I have a little funny story to tell related to temples, once my friend and I went to Kamakura, an ancient capital near Tokyo, to do some sightseeing. We ended up visiting a temple which turned out to be famous for divorces, apparently in the past, when women couldn’t divorce, they’d run and hide in this temple which will then force divorce upon their husband. My friend was laughing that we shouldn’t have come here, well fast forward one month, we both broke up with our boyfriends, met again and decided to go visit one Tokyo temple famous for helping with love matters. We went there just for fun tbh, but we prayed to meet the love of our life and each of us purchased an amulet. I ended up meeting DH-to-be in 3 days and my friend met her future husband in about a week, I think. I must admit I went back to this temple after having a not-too-friendly first meeting with future MIL, prayed that we have a good relationship and she started treating me like her own daughter and we are really close now. Might be a simple coincidence for all I know. 
I’ll include a couple of pics I’ve taken in Tokyo over the years.