Some good advice in this thread. I also find when sealing anything that has moisture or liquid it helps to "hang" the bag off of a table. I place my unit on the edge of the washing machine so I can hang whatever I'm sealing vertically. Gravity does it's work and bags seal up fine.
UDS'-55&16, Akorn, Bar-B-Q Kettle, Drum Grill, miniWSM, cobweb-covered gasser. I'm JD.