Edit: devo you beat me to it lol. But heres my advice.
Make sure your "regs" are nice and dry. The drier the better basically. When i first got my extreme v3 I had to by weed, you know that good "dro" stuff
I noticed its almost always too wet to use. And dont get me wrong im not saying it was wet or fresh, just not dry enough.
Im not sure what you expect to see, but it will not be nearly as thick as smoke. It should have a subtle blueish hue to it. I also find if you have a white roof/walls it makes it hard to see any vapour.
Also why do you warm it to 300 and then use it at 500, warm it up at 450 for 10 mins with the empty bowl on it, then turn it down to 400, this ensures it will be at least 400 and gets the glass all warm, put the packed whip on there and hit away. Alternately you can just turn it on to 400 and let it sit for 10 or so mins, but u will find that turning it up a bit higher will allow you to get a warm up time of like 2-3 (for later reference). Dont need to let the weed percilate per say, because you drawing on it will bring the hot air through the weed and warm it upu faster anyways.
Keep with it, youu will have it dialed in no time.