I'm actually making sushi tonight! I've got the rice cooling on the bench as we speak.
Use Japanese short grain rice. It sticks together better than other types of rice. If you can't find it in an Asian grocer or in the Asian section of your supermarket just look for where the Sunrice specialty rice is kept. The Sunrice one is in a black bag.
You can buy Japanese sushi vinegar or make your own by mixing sugar with rice wine vinegar and stirring it through the rice before it cools. Recipe here
When it comes to rolling the sushi, the best thing I've found is a sushi press. You wet it so the rice won't stick, put it on top of a sheet of nori and fill it with rice and whatever filling you choose. Then you press down to compact the contents. Remove the press, wrap the nori around it, wet the ends of the nori and it will all stick together. Traditional sushi presses are made from wood (you can find these at Japanese supermarkets or on eBay), but my mum got me the Sushi Express which is made of plastic and is very easy to clean (link
). You can also buy sushi presses which don't require any nori. The rice should hold its shape and you can just top it with sashimi or pickled vegetables. Or you can buy them in cute little shapes to use with rice alone in order to use in bento boxes (example
If you prefer to use the traditional bamboo mat to roll it my advice would be to put a sheet of glad-wrap between the bamboo mat and the nori. That way once you've rolled it up you can twist the ends of the glad wrap and you've got a handy wrapper for the nori roll. Leave it in the fridge for a while for it to 'set' and it'll be far easier to cut.Here are easy to follow instructions for rolling sushi the old fashioned way.
Make sure you use a really sharp knife to cut it. That way it won't tear the nori.
As to fillings, I'm vegan so I'm a bit limited. I use raw carrot, raw cucumber, finely sliced spring onions (green onions or shallots depending on which state you live in), pickled ginger, sliced marinated tofu, avocado, and/or sesame seeds.
If you don't mind fish you can use raw fresh salmon. If you don't have access to fresh seafood (it has to be reeeeally fresh) my family have been known to use smoked salmon instead. You could also use tinned tuna or cooked chicken. Here are a whole lot of sushi recipes
Hope this helps!