Hey man, I've only traded a few ETF's. They move very very fast. Be sure to watch it close with the index, for $UGAZ, obviously Natural Gas. I used to get into trades a lot without a plan, set risk, etc. My only advice would be to trade the plan you had getting into the trade. If there was no plan of what price to risk on, then I suggest making one. I didn't follow my plan on $CALA and got squeezed like an organic lemon. Whenever I enter a trade, I have a set risk that when it hits, i sell, or well, try to anyways. Emotions, etc will always be a constant battle lol.
Keep in mind I'm totally new to day/swing trading these things, and learn something new everyday lol.