Get Knotted.
It could be a song but its true to say a good knot is hard to tie a good knot! Or is it? With lots of practice a good knot is the fishermans best friend especially by the river bank in winter and your fingers are numb!
When a knot unravels or the line breaks near to the knot under pressure then there can be a number of causes for this.
When using a nylon line then as you know this has a very slippery surface. Its natural tendancy is to slip and when you reel it in if the end of your line resembles a pigs tail then you know this has happend.
Also in line strenghts under 10lb the line can suffer abrasions knicks and general abrasions very easily thus leading to significant loss of line strength. Indeed just tying a knot and pulling it tight can damage the line considerably but it is safe to say that some knots can cause more harm than others.
Pulling a knot tight will cause friction and heat this creates can in extreme cases melt the line and therfore to avoid this always lubricate your line with something wet before you pull it tight.
Use even pressure to tighten your knot by pulling it tight quickly will lead to a loss in elasticity and strength.
Get twisitng - where your knot involves twists of the line it is always recommended to use at least six twists no less this will mean your knot is less likely to become unravelled under pressure of a fat fish on the hook.
Generally an effective knot should look tidy. If your knot is a mess start it again as it probably will fail.So ask any old wise fisherman and he will tell you to practice them thar knots my friend and practice them lots in bed at dinner even in your sleep just practice.