1: green tea prefers a brewing temperature of around 165f-175f. If you don't have a kettle that does temperature (i didn't until last year), just let your water sit for a few minutes after you let it boil to cool down.

2: Bagged green tea tends to be not worth it imo, I'd rather just drink average coffee at that point.

3: A lot of sources say to brew green tea for 3-5 minutes but golly that's way too long. 90 seconds is enough unless it's tea in a teabag (in which case refer to #2).

3b: If you've wanted to like green tea but find it to be exceedingly bitter or that it imparts a sediment-y feeling in your mouth, you're probably steeping it for too long.

4: Most leaves you can re-steep 2-5 times. 3 is my sweet spot for myself.