Just got my Gen 1 Prius

(0) read the sticky in this thread "Who should and should NOT buy a Gen I Prius"
(0.1) MAKE SURE YOU HAVE A BACKUP CHIP KEY!!! (see the next sticky)
(1) get a good quality code reader
(2) get a mini-VCI OBDII adapter and Techstream software on a Windows laptop for in-the-weeds problem diagnosis
and general battery health information
(3) Give it a good tune-up - plugs, filters, oil change. Keep a maintenance/repair log.
(4) Peruse this Generation I Prius set of conversations for all the fun stuff to tinker with.
(5) Don't be afraid to ask questions in this forum...
(6) You may find the 175-65R14 tyres are becoming tough to find...
Welcome to the club!

 

The biggest factor in gas mileage in any vehicle is obviously #1 the thing's design and all of that. But #2 is just the nut behind the wheel. Don't become a hyper-miler (it's obnoxious), but learn to drive "inspired by" hyper-milers. It's literally the biggest thing after vehicle design that will matter.

I don't have any idea what enhance "user experience" means.

Sounds to me like you just want to do a lot of reading in this Gen1 subforum. No one is going to write you a book.

 

It’s well worth noting you can easily order a set of 165/65r14’s that Fit a Honda Insight or Mitsubishi Mirage, adds an easy 10-20% if you keep them aired up

 

congrats and welcome!

i have never owned gen 1, but i see some pretty tricked out models from time to time. check jdm in japan

 

Turn off the display
Clean the throttle body
Air up the tires