First of all, always have 2 fingers on your rear brake! Make it a default when riding.
I started by putting my legs down to the ground and then drive and pull up the scooter.
That way you can't tip to the side, you only have to focus on the vertical.
But be careful! If you give it too much throttle and can feel that you're gonna overwheelie. You will seriously crash, because it's much easier to overwheelie with your legs down.
When you think you got that thing going pretty good, start by putting one of your legs to the footpad and then try wheelie again.
No matter how boring or hopeless it seems, you just have to practice alot more
Everyone who can wheelie really good have all been there!
Practice, Practice and Jerking around on you scooter is a great way to learn the limits and stuff about you scooter!
Sorry for my bad english!