Everyone has their own preferences for knots.  Learn at least one good knot for each application.  Practice – Practice – Practice,  until you have the confidence to tie them quickly on a moving boat in open water.   That confidence pays off during a hot bite!    Knots for various applications include:

Instructions on tying knots is available on YouTube and these two excellent knot tying references:

Net Knots

Knots by Grog

MBMC Knots