OK, a few suggestions for good quality Gyokuro brewing. This will not really help mediocre or bad gyokuro. And BTW, Gyokuro is similar to Long Jing in a few respects, both are green teas and both are commonly not the real deal. Often tea sold as Gyokuro is Kabusecha or worse. Brewing Kabuse rich as I outline below will not render desirable results.
2:1 ratio is common around here for brewing good Gyokuro. But if the Gyokuro is exceptional, you can amp it up even more. 3, 4, more grams per ounce ... I am most often in the 2-3 to 1 ratio range.
PREHEAT everything, pot, cups ... you can actually do this as you cool the water down ...
COOLER water, it is not uncommon to go 120-130* or even cooler for the first steep. Then for subsequent steeps, increase temp by 5-10 degrees.
Then you can increase time as well which will result in a deeper flavor profile. 90-120 seconds for the first steep. Try 90. Subsequent steeps, 2nd 10-30, 3rd 60, 4th longer, etc.
Good water! I won't get into this here ...
The Japanese refer to Gyokuro as "precious dew." Therefore, small steeps reign. I am usually in the 1-3 ounce range, 2 is average for me. Obviously small cups are a big help ... and as I already stated, PREHEAT the cups.
I usually make 2 cups, 1 ounce each.