what everyone's said. Assuming you're geared, it took me about 15 minutes a day for a week of dedicated practice to get a rudimentary standing trackstand together. The following week I was juddering around at the lights. There's a tendency to look down at the front wheel – try and keep your head up and look straight ahead. You find you use your brakes a lot in the beginning, but you won't need to use them at all after a month of so.
Also it's easier with your front wheel turned to the right. As we drive on the left, there's commonly a (barely discernable) uphill sloope towards the middle.
Once you've got that sorted, try it seated – it's much more relaxing at the lights. If you want to trackstand downhill, put your foot on the front wheel and drag it backwards to get the backwards motion – surprisingly easy. And then there's everything no handed which comes after a few months of daily commuting.
Wheelieing – well that's another story. Year and counting.