Does driving on low rpm’s save the most gas?

Keeping the vehicle under 2000rpm’s will always save the most gas and while on the highway at a steady speed maintain the 2000rpm’s.

If you look at the engines torque/horsepower curve, the best place to cruise is where the two lines cross. This is not the same for every engine. The best thing to go by is where you have to use the least throttle to maintain speed. I can go up a hill at 35 in fifth gear, something I was forced to do to limp a car hope, but the gas pedal was further down to the floor then if I would have been in third or second. That was the worse fuel efficiency the car has ever gotten.
Also being in to low of a gear shortens engine life because of the strain on the rings.
So look up the engine performance curves and see where the lines cross, shift in such a way that you cruise at about the point where the lines cross.

2500 RPM’s is historically the number that you shift at. Shifting earlier isn’t always better. Keep in mind that different cars are at different speeds when you get to that 2500 RPM’s when you are in a different gear. Accelerating slowly is always the best way to save gas, but remember that driving at speeds of 25 MPH is usually the worst on gas mileage. This is why cars get higher MPG when driving highway than in the city. I would say that what you are doing now is just fine. Also, just remember that it is a manual and you can go up an extra gear. So, when at 55 MPH go to fifth gear instead of staying at fourth or go to third gear when going 25 MPH. Pretty much just keep on doing what your doing. You are doing the best you really can with what you got right now. Best of luck.

Without knowing which vehicle you have, this question has a lot of unknowns. If you have a large displacement V8 engine or a diesel engine, shifting at 2K RPM is sufficient. However, if you are driving a small displacement 4-cylinder gasoline engine with widely spaced transmission gears, shifting at 2K may be too low. If the engine “lugs” or vibrates when you shift into the next gear and continue to accelerate, you are shifting too soon.

It all depends on the characteristics of your engine. Generally, yes, you save some fuel shifting at low rpm, but don’t overdo – engines are not particularly happy about it.
Reducing acceleration is a very good method, as is reducing stop-and-go (which unfortunately we can’t fully control).
The best shifting method is the one that gets you close to the max. torque value, which is where any engine is most efficient (ie, burns least fuel for a given output). To save more, shift up slightly before the usual (normal) rpm.
Also, slightly overinflate your tires and throw out any load you keep in the trunk, keep the car in good mechanical condition.

generally yes.
however it is better for engine with manual to be run at little higher rpm than lower rpm if given a choice.