I've given this site before and if you are going to tie your own this is a great start for you.
http://globalflyfisher.com/fishbetter/leadercalc/
I use a standard 9' 5 piece formula (this is for a 5wt):
3' butt of .50mm (you can either tie this direct onto you line using a nail knot or use a 2 turn water knot to form a loop)
1' of .40mm (I use a 3 turn blood knot to join the two sections
1' of .30mm (Again I use a 3 turn blood knot)
1' of .20mm (now I use a 4 turn blood knot but you could use a 3 turn water knot
3' tippet of .13 (I join this section with a 3 turn water knot which allows me to add a dropper. If I want a dropper higher up, then I attach say a 4x piece using a nail knot).
This formula is easy to remember, works extremely well and has stood the test of 1o years of guiding.
Now the secret of good leaders is the butt. It needs to be about 2/3 the thickness of your line tip. You may need to experiment a little with it.
Another site for you is about knots.
www.netknots.com
Cheers and the the effort will be worthwhile.