In the past few years, I've attended many track schools. The essential message in all was the same: to corner faster, to lean over more, you need to be smoother. The reason is simple. The further you lean over (which happens when you start going around corners faster), the less available grip there is. Being un-smooth makes it more likely that one of the inputs will overwhelm the available grip and cause you to fall off. More often than that, however, it causes your bike to feel weird and stops you from going faster because your brain screams enough.
The trick to unlock corner speed begins with throttle control. The simpler aspect of throttle control which dealt with in this very section in short many times is that your application of throttle should be a progressive movement. It means that the torque reaching the rear contact patch should increase (and indeed, decrease) in a linear fashion. Visualise it as a smoothly rising line on a graph, if it helps. This applies to both the opening throttle and the closing throttle. Sudden throttle inputs cause your suspension to react just as suddenly which will destabilise your motorcycle and potentially bring you closer to crashing. The mark of good throttle control is minimum suspension movement while you turn in, reach the apex of the corner and as you power out. What suspension movement is there should occur progressively.
So, how do you build smoothness You practice. In a parking lot or on a deserted stretch, first try getting a feel of things. Stick the bike in first gear and try rolling on and off the throttle without upsetting the suspension. This is hard initially, and it will require steady, smoothly moving hands visualise Rossi's if that helps. Don't try it in the higher gears. First gear is low enough to amplify the suspension movements, and you're just looking to get a feel for the sudden expansion and compression of the front forks. Then take it into the turns. Most riders normally complete corners in a series of throttle adjustments. Street riding accepts this with no problems because you're nowhere close to the limit. But you can do better.
Start out by entering corners slower. What you're looking for is the ability to start rolling the throttle back on after you have turned the bike into the corner and then keep applying more and more throttle progressively until it's properly open as you pass the apex of the corner and head for the exit. Initially, forget the corner speed itself and just focus on rolling on the throttle steadily. Mentally focussing on the rear contact patch the bum is a good place to get a feel for it helps immensely.
Once you can roll on progressively, you can start trying to find out how quickly and how hard you can do this without violent suspension movement. If you're out practicing with friends, get a buddy to watch your throttle hand for sudden movements. Remember not to look at the throttle hand as you do this. You must still be looking through the corner as you normally would. Practice at a safe place; it goes without saying.