The secret is to keep your hands and knife moistened.
Place one sheet Nori, shiny side down, on a board (or Sushi rolling mat).
Moisten fingers.
Evenly spread 1 cup of Sushi rice over 2/3 of Nori, with the uncovered part away from you.
Make a slight indentation in the rice (just your side of half way up the rice)
Fill the indentation with one of your fillings (as above).
Slowing roll up (keep fingers moistened).
Cut roll into 6-8 even pieces with a sharp knife (moisten knife to prevent sticking).
Notes
For the rice basically just follow the instructions on the pack then flavour with rice vinegar, sugar and salt. Serve with soy sauce and wasabi (Japanese horse radish sauce).