Initially, You need to build a base level of fitness so going for a jog at a pace you are comfortable with and slowly increasing the speed on each subsequent run is fine. This will be working your aerobic energy system predominantly.
But long term that's not going to help as much. If you want to be fast, you train fast and you increase your training intensity or volume.
Having good anaerobic capacity/lactate threshold is just as important for running as high vo2's.
Steady paced training won't do anything to stimulate changes in you anaerobic energy system/increase your lactate threshold.
Obviously you don't train flat out all the time and you need to make sure you get your recovery time in. But the basic principals are the same for most fitness type things, progressive overload (through volume, intensity weight etc) and you tailor them to suit your goals.