I would suggest 20-25mph in 1st gear, anything slower your gonna have to worry about side to side movement. Sitting down is what I was practicing on then maybe go to staggerd stand ups,left foot on passenger peg/right over the rear brake (just what your more comfy with, everybody is different). Don't even worry about looking at the RPM's, you should be looking/consentrating forward or at the front fender. Keep your knees pressed into the gas tank, snap clutch & throttle at the same time using 1 finger on clutch, start SMALL & go bigger/longer. Once u get it up to your desired hight, let off throttle SLIGHTLY & start modulating it (very small movements) carrying them longer & longer each time. Cover that rear brake, although engine braking is great in 1st gear. Ride safe/wear your gear, take baby steps, & of course practice practice practice!!!!!
Oh yeah, if you haven't been riding long. Take a year or so to get to know your bike, cuz throttle control is Key.