Secret to longlining is you never stop or slow the boat while the lines are out. If you do you'll have all of them fouled on the bottom, so you reel the fish in while underway and most times you can work the fish in a straight line and avoid tangles. A long handled net helps too.

Note: Stripers, Gar, Catfish, and some other ignorant species have not read this and refuse to abide by the rules.