Warm your vinegar, salt & sugar in a pan until the sugar & salt have dissolved.
Leave this to cool as this is your sushi vinegar.
Wash your rice 3 times in cold water (massage the rice, making the water cloudy) After each wash, empty the water & use fresh for the next wash.
Leave the sushi rice to stand for about 15 minutes.
Whilst you are letting your rice stand, bring a pot of cold water to the boil. (about 1 litre for 750g of rice so if using less rice reduce the amount of water accordingly!)
Add your sushi rice & let it simmer with the lid on for 10 minutes.
Remove the sushi rice pot from the heat & leave to stand for a further 15 minutes (don't take the lid off)
Tip the cooked sushi rice into a plastic or wooden bowl and evenly pour your sushi vinegar mixture over it. Mix it in gently using a wooden utensil, this will dry the rice & make sure you have an even spread.
Allow the rice to cool, you can fan it gently to quicken the process. The rice needs to be at room temp to use & it should be pretty sticky.