For skids, just ride more until you have good feelings and start to lean forward to lower the weight on your rear wheel.
The more you lean , the longer you skid. I prefer learning long skid stopping first and then get into the shorter one because you need your muscle to learn the move.
Some people suggest pushing their foot inward so that it's like locked, could be easier to skid.

I learnt trackstanding first in a sitting position because I found it much easier than standing on the pedals. (sitting -> one hand-> no hands ->standing cause i am a weirdo like i can ollie on skateboard when moving but cannot while at rest). Maybe you can try it sitting too not much to teach because trackstanding is all about feelings, once you get that you just rock

one question , what kind of handle bar you are using? That kind of matters.