Nori rolls at home: ultimat...

The other ingredients you'll have and want will include filling and seasoning ingredients.  All the filling ingredients should be cut into narrow but long strips or wedges.  In the picture, I have (left to right) enoki mushrooms, tamago omlet cut into strips (you can do microwave scrambled eggs and cut them into strips), avocado cut into small wedges, shredded green onion, matchstick cucumber, and matchstick carrots and strips of red bell pepper.  These last two were blanched in the microwave to soften them.

I also have some fish, of course.  Importantly, do not buy fish for sushi unless you live somewhere you can get "sushi-grade" fish you trust.  It has to be very fresh and inspected for parasites, and you can expect to pay $17/lbs to $30/lbs for it.  Don't worry though, you only really need about 1.5 oz of fish per nori roll, so you don't need to buy very much.  Slice the fish across the muscle grain.  You can also use shrimp, which doesn't require sushi-grade; get raw shrimp, shell them, split them down the middle and remove the veins, and then lightly steam them pressed flat (you need to keep them from curling up).  Or buy shrimp from a Japanese market. 

You'll also want some seasoned soy sauce, if you can manage it.  People have various recipes for this, I use:

5 tbs high-quality shoyu soy sauce

2 tbs dashi or somen broth (substitute light soy sauce)

2 tbs sake or mirin

1 tsp sugar (unless using mirin)

Get out your trusty butter-warmer and bring all of the above to a simmer, stir a bunch, then let cool.  If this is too much effort for you, of course you can use just soy sauce -- look for milder, less salty soy sauce.

Other seasonings include toasted sesame seeds (white or black), pickled ginger and wasabi.

The mat you see under the nori is a sushi rolling mat; it's made of many small sticks of bamboo bound together so that they roll up very easily one way but remain rigid the other.  If you can't find one, don't dispair!  Many cheap bamboo placemats are made the same way.  Or you could get a sushi-rolling gadget; there are many.

Assuming you're not rolling a gadget, the next thing you do is press rice out into an even thin layer on the nori, leaving about 1/4" on the bottom and 1" on the top.  This is more easily done with wet hands, so you might want to keep a bowl of cold water handy. 

After that, you add fillings for the nori roll.  Above I have a red snapper-cucumber-green onion roll and a shrimp-egg-avocado roll.  It's not a good idea to get carried away with too many fillings; the roll won't hold together and won't taste like anything.  In both cases, I painted the seafood lightly with seasoned soy sauce.  The shrimp roll further had a tiny smear of wasabi.

Next you'll use the sushi mat to roll it up tightly.  The extra margin of nori at the top should go to seal the roll, you might even wet the overlap a little.  Don't worry that it takes a while to get the sushi rolling right; your first couple rolls will fall apart, but after that you'll get the hang of it.  And even misshapen rolls still taste good.

After that, you slice the roll.  This really requires a very sharp, very thin knife (I used a filleting knife), which should be slighty wet to prevent the rice sticking.  If your rolls are tearing, then you probably need a sharper knife.  Cut the roll into 1" slices, with the end pieces extra tall to keep them falling apart.

Arrange them attractively on plates, and serve with seasoned soy sauce in little dishes and pickled ginger (which is a palate cleanser between different types of sushi).  Since nori rolls are eaten with hands, kids generally love them.

Also, one batch of nori rolls serves a lot of people.  This is the "spillover" plate.  I think this batch of seven rolls served four people a full meal.  Elapsed cooking time was about 4 hours though, so plan accordingly.

And enjoy your sushi!