Greetings, Civic4Ever!
To echo MobilOne, definitely add a gauge of some sort, whether ScanGauge, EcoMeter, OBDII Dongle/Smartphone app, or something else shiny.
California98Civic suggested airdam and grill block, I've been rolling with both, but I just ripped my air dam off. Working on something new.
I posted a grill block video last month:
https://youtu.be/RVzra5e4rpc?list=PL...R754kIg_V8Aahm
Go with synthetic oil and a good set of low rolling resistance tires when it's time to change.
My fave mod so far, dollar for dollar is a B&M short throw shifter ($60) and Energy Suspension poly shifter bushings ($10).