Turn your AA up to the max.
It kinda hurts my eyes. Seriously.
It’s not bad for a first try…but I see you maybe copied and pasted and forgot to change the canvas size, seeing the white at the top. Smoke looks pretty unrealistic.
Here, this might be useful. You can use this to learn how to make good smoke: http://www.facepunch.com/showthread.php?t=283819