First I am demonstrating: How to form a Blood Knot
And then, tying it under 30 second connecting actual monofilament fishing line. I am demonstrating one of the famous fishing knot - Blood Knot that usually in use for tying monofilament fishing lines. It is a very reliable knot. You just need to be sure that you will have minimum 4 turns from each side of the knot. This video is a part of the play list: "Tie any Fishing Knot under 30 second"  

A blood knot (barrel knot) is most usefully employed for joining sections of monofilament nylon line while maintaining a high portion of the line's inherent strength. Other knots used for this purpose can cause a substantial loss of strength. In fly fishing, this serves to build a leader of gradually decreasing diameter with the castable fly line attached at the large diameter end and the fly or hook at the small diameter end. The principal drawback to the blood knot is the dexterity required to tie it. It is also likely to jam, which is not a concern in fishing line, which is no great loss to cut, but may be a concern in normal rope.

Tying the knot
In tying the blood knot, the two lines to be joined are overlapped for 6–8 cm with the short ends of the two lines in opposite directions. The short end of one line is then wrapped 4–6 times around the second line and the remaining portion of the first short end brought back and passed between the lines at the beginning of the wraps. The short end of the second line is then wrapped 4–6 times around the first line and the end of this line brought back and passed through what is now an oval space between the first wrap of each set.
Watch the video for details