Accelerate quickly to the speed you want and then choose the highest possible gear to keep the revs low. Try to adjust your speed to reach the traffic lights, even if you have to go at a slow speed. The idea is (almost) never to use the brakes and keep the inertia of the car moving. All I did was step on the accelerator a little more gently.
I had no problem keeping up with traffic. Properly lubricate all moving parts that you don't want to waste energy. Replace all filters during maintenance. Clogged air filters mean less efficient combustion.
Clogged pollen filters mean additional energy loss. How can I tell if my car does this? How to modem? I always use neutral. Check your tire pressure from time to time, make sure it never goes down, keep a light load. Eliminate anything unnecessary, do your best to keep your revs low, even if that means getting stuck driving slowly.
A small engine manual car is probably the best thing you could use to deliver. Try to make a slow stop at the traffic lights. If you can keep it moving, the 1-2 mph you will travel will reduce your gasoline consumption when you take off. Drive a manual, keep it at low revs, always keep it running while moving to take advantage of the fuel cut, use the factory recommended wheel and tire dimensions.
I had recommended the fuel injection service. I've definitely noticed that I get better gas performance at certain gas stations and worse at others. The car will waste more gasoline trying to regulate the speed going up and down slopes, so unfortunately you'll have to worry about your accelerator pedal account. Brushed DC motors are (generally) more efficient at low speeds and for traffic and it's best to switch to gasoline when you're on the road.
To answer your original question, the most efficient way to approach that hill is to increase a little speed before the hill (ideally through momentum) and just accelerate it on the way up (stay in your maximum gear). Over time, you'll also notice other things that affect your fuel economy (my car burns about twice as much gasoline when idling while warming up). It saves you gasoline in the long run, especially when combined with the more efficient speed of approximately 55 mph. Take your foot off the accelerator in time to go half speed in tight corners and accelerate when cornering.
The added benefit was that these practices are also safe driving practices and resulted in a reduction in traffic fatalities. However, older cruise control systems only use reactive measures to maintain speed, so going uphill will force cruise control to use more gasoline than necessary. And the best way to reduce fuel consumption (up to double what you've saved by following the steps above) is to not use any cars. It will vary a little from engine to engine, but it is generally a little lower than that of a gasoline engine.
It sounds contrary to intuition, but it boils down to reducing the time the car accelerates, within certain parameters. Now you don't need to waste gasoline and endanger your life and the life around you by driving recklessly.