I managed to lose about a quarter of my fictional balance in less than a year, even without leverage. I'm sure one could manage to lose that kind of money a lot faster using leverage!
It wasn't even that I was losing money by trading too often. I think during the period I was trading I made fewer than one trade a month. However, I was quite good at guessing wrong. You could have guessed more wrong if you'd tried, but it would have taken effort. Most of my positions ended up being losing ones.
Speaking of which, I also realized that while the graphs are pretty and the quasi-real-time quote board can be mesmerizing, I just couldn't summon up the focus necessary to stay on top of the markets.
A bit of self-knowledge and humility bought at the price of a small amount of time, and no money at all. I'd call that a win.
*As the article says, "Whether market timing is ever a viable investment strategy is controversial."