Completely agree with flights.google.com
I will say that for my trip last month, I found the cheapest JL fares to come out of LAX so we did a positioning flight with miles from CLT to LAX
Not knowing where you are located at, if you routinely fly out of a hub (say CLT where I am) look for local airports an hour or so drive from that hub as origination...that can cut 20%+ off the cost sometimes
Sakura season (just starting now) is always going to be expensive
I could go on but with the limited info given, this is a start