1) NO stop-loss to protect the account (should be 15% - 20% below your entrance points). Must, must, must to have this habit. If not, even you have 1 billion dollars, you will lose all eventually.
2) Always buy in wrong entrance points and hold for a long time (you can't hold these 3x etfs for a long term such as 1-3 months). The huge decay and big swings will kill you no matter which side you buy.
3) When buy in a really good entrance point, expect to make the fast money right away. There is NO FREE lunch, OK!