I fly about 10 cross-country (SFO-BOS) flights a year, mostly on JetBlue aircraft.
If you want to change flights on the same day, you can wait until the same calendar day as your flight and call to change flights for a fee of $50. This is a great option if you don't want to spend the whole day waiting at the airport.
JetBlue allows you to pool points within your household, but only one person can be the "head of household" and redeem the points. Changing this person involves an obviously tedious call to JetBlue, so get it set up right the first time.
Typically, JetBlue boarding starts from the back of the aircraft, so a seat closer to the back (generally not in rows 5-10) means you're more likely to get an overhead berth for large hand luggage.
The front has some advantages: if you plan to buy any paid food items (sandwiches, etc.), they start taking orders at the front of the aircraft, and sometimes run out. Of course, you will also get off the plane first.
Wi-Fi is now generally available on flights to the US. Browsing is free, but you need to pay by the hour to do anything else, like upload files. Unfortunately, the paid version does not support a very good connection. Not worth it yet.
The ginger ale and chocolate chip cookies are terrible, but the other food/drinks are quite good.
Ask for two snacks if you are hungry; I have never been refused.
To turn off the screen, turn down the brightness completely (obviously, but some people don't know). The screen is not touch.
The first bag registered is now $25 on JetBlue, so keep that in mind when you compare prices with other airlines (they were free in 2015).
Sign up for their promotional emails - they send out some pretty solid discounts.