Get it out of the pan about an hour before, so it comes up to room temperature.
Salt and pepper on each side.
Get the pan properly hot.
If it has fat down the back of it, stand the steak in the pan, on the fat, it will melt and oil the pan for you.
Chuck it on one side for about a minute.
Flip it on the other side for about a minute.
If it's not well hung (matron) you will need to cook it a bit longer, as it'll be tougher. You should only buy steak from a good butcher and make sure you ask for the oldest, longest hung steak they have. You also want it marbled with intra-muscular fat, if possible. It will be duller red than the bright red stuff you get from the supermarket, but it will be far more delicious and melt-in-the-mouth.