I have never attempted to make my sushi rice differently than my normal rice. I know there are sushi rice recipes that call for rinsing and draining the rice several times before cooking, but I simply don't care enough to go through that effort for (at least what I perceived to be) almost no difference in the end product. I also don't bother paying extra for sushi rice, I just go for my normal basmati or jasmine, whichever is cheapest.
That said, here's my method. Add equal partsone part rice and two parts water to a stock pot. Cover and cook on high until boiling, then reduce the heat to as low as possible. Don't take the lid off until the very end to taste test. Don't stir while it's steaming. I don't set a timer, I simply check in 10-12 minutes until the rice is done. (I know when it's done by tasting it, you can tell it's getting close when there's not a lot of water left in the pan.) This method works very well on a gas range. I just moved to a new place with an electric stove, and I've realized I have to heat the rice lower than the hottest setting so that when I turn it to low it doesn't boil over.