Any more sanding tips to help reduce swirls or pigtails?

Wipe off your work before you start and also between grits.
Adjust your suction to closer to minimum - you don't want to suck the sander down into the work.
Start your sander off the work surface and lift it off before turning it off.
Sand in patterns - go side to side and then top to bottom so to speak. Go methodically and overlap your patterns.
Use a raking light to check your progress - particularly at the end prior to applying finish.
Let your sander do the work - don't apply more pressure than necessary to keep it on the surface - see #2.
Check your sandpaper to make sure you don't get anything stuck on the paper which would create a lump.
Check your Velcro on the backing pad for debris as well as on the back of the paper.