Problem is that "hard throttle pressure" is a squishy term. Optimum efficiency comes with low rpm and about half to three-quarter throttle. Do not creep away from stoplight with pressure just above idle- that wastes gas.
With stick shift, shift early to keep rpm low, but hold substantial throttle opening, half to two thirds. With auto, one does not want to delay shift, but still keep a reasonable throttle opening, maybe forty to fifty percent.
All of this is, of course, predicated on traffic conditions where you can accelerate as you like.
Also, avoid brakes! Every BTU of heat your brakes give off comes from your fuel tank. Some people feel tailgating improves gas milage from aero effects- not true. Increased brake usage from tailgating far more than overcomes any slight aero advantage.