The biggest thing here to keep in mind is to NOT expect too much too fast. You said it best in you question "over time". You have to start slowly, and work consistantly. Never try to advance too quickly. It takes alot of time and hard work. I think the reason most peeps fail is because they are not willing to put in the hard work. Work slowly woth a metronome, and build up over a series of months (not days)

There is no silver bullet here. It all comes down to blood,sweat and tears. If you put the time in, you will develop speed.