Best way is NOT to count the links. That's the #1 way to mess it up.
Install both new sprockets.
Placee the rear wheel where you want it
wrap the new chain around and then confirm where to cut and cut it down. (remember to leave room for chain slack).
Also remember you can always take more links out so if you're not sure error on the side of safety.
I also always put the rivet link through the chain to connect it then have someone hold it on there while i adjust the rear wheel. When i'm sure it's perfect and cut perfectly only THEN do i actually rivet it on.
I hope this helps and if you have any questions just post up, shoot us a pm, or give us a call/email.