help mastering quantization

First quantizing won't help much if your timing is out buy more than the amount your trying to use. Like say you hit a note and your timing is more than an 1/16th late. If you quantize to 1/16 the note might end moving in the wrong direction.  I won't go into the complicated stuff and there are settings to help, but most of all you need to know what the finest note value you played was. Before your quantize Open the PVR and look at the grid lines. Where are your notes sub dividing ( or close to) ??  Maybe your playing in triplet time. Shuffles and the Blues use triplets. They show at 3rd spaces between the grid. You can turn different grid options on or off to help you see.  I keep the grid on 1/8  or 1/16th notes  because an 8th or 16th triplet can be done by eye.  
 
I think a lot of us quantize in small sections on complicated stuff. I often will just quantize my kick drum and hats and manually edit the rest of the kit. But then I do try and play very close to what is correct. I bought a basic digital drum kit for this reason alone.  For keyboard parts I often cheat and slow the song down a bunch. That's why it's good to start with Midi only or at least have a midi only option. .   
 
 Make sure you have no latency in your monitoring as that will result in pour timing too. Your sounds should be instantaneously the ms you hit the keyboard or pads.