Dario
I nail knot a tapered leader to the end of my flyline, then fish a tippet of the same strength. Usually the taper ends up about 8ft and i'll use a tippet of about 4ft, If i'm using droppers then i'll step down after 3ft of tippet to the next "X" down and have another 3ft .ie 5X taper, 5X tippet, 6X tippet.
Using tapers improves turnover dramatically as it provides a smooth transition of power along the flyline and into the leader right down to the fly.
It makes a huge difference to the presentation of small nymphs and any Dry as they often don't have the weight to straighten out the leader and can put up greater resistance against the air, so a proper power transition helps a lot.
I wouldn't use anything else.
Sandy