I'm not a knot specialist and don't have the claim to teach you how to make good knots... I should at first learn it myself !!
However, the few knots which follow are very usefull to me and will certainly be for you as well.

plat

The reef knot.
Remarkably adapted for connecting two ropes of same diameter together.

CAUTION, do not use when the 2 ropes have a large diameter difference, it would not hold !

 cabestanCapstan knot

This knot is very useful to attach a rope to a mast or a stake.
It resits remarkably to traction and can be detached very easily.
Certainly the most useful for us.

 
ancre
 Anchor knot

This knot is used to attach a rope in a provisional way. It can be detached very easily.

 
 
chaise

Chair knot

This knot does not tighten with traction. It is well adapted to replace an eyelet.
Useful for attaching a rope to a mast.

 
 
noeudOK

This is a very clever knot i discovered while meeting some OK stations who came here in Corsica for a VHF expedition.

Made at the end of a rope, it is used to tend a wire guy. The moving part being blocked by the fixed one, the tension making it tighter. That's an easy way for adjusting the wire guy tension.

On the left of the picture, you must imagine the rope making a loop around a post, and the right one attached to the mast.

I was doubting of the strurdiness of this method, but i must admit that it stayed safe during all the windy expedition !

You have certainly understand that i'm not a sailorman and don't know a lot about knots. I ask the pros to be indulgent...

 

Last products !