Canteen fishing is a super easy way to reel in a fish, and you need surprisingly little to make it work.
Canteen fishing is exactly what it sounds like; you use a canteen instead of a fishing rod to catch fish. It's not quite as different from normal fishing as fishing in a hole is, but you can probably get similar results.
Even if you don't have one of the Readyman's Fisherman Cards you can still use this hack by just keeping a hook, lure, and some line handy. In all honesty, you don't even need the canteen, but it does make it a little easier to keep track of your line and to "reel" in slightly bigger fish.