A gasoline engine is most efficient when it runs around 80% engine load, and very inefficient at low loads. I shoot for 85% engine load when I accelerate, but the truth is that engine load isn't very useful for steady cruising because it doesn't take that much power to maintain speed.
This is the reason why the pulse and glide technique is fuel efficient. The engine is run at high load briefly, and then the car is coasted until it's time for another speed boost.
Timing advance isn't too useful either except that it can be an indicator of engine warmup (timing is retarded when the engine is cold), intake temperature (too hot and the timing retards), acceleration (timing retards during higher engine loads), and fuel grade. My Acura specifies 91 octane, but can run on regular 87. This comes at a cost of slightly retarded timing. Fuel economy generally improves with more advanced timing, so everything is a balancing act.
As a beginner, the main thing to focus on is avoidance of using the brakes. This means anticipating what traffic will do, looking down the road to see what traffic lights are doing, etc. Usually this also means leaving a larger gap ahead of you, so that you have time to coast or change lanes.
Braking is energy wasted. Other details such as engine load are very minor compared to what is lost due to unnecessary braking.
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