Sounds like you already have some really good pointers. I agree it helps to start with a good cut of beef however I grew up with plenty of good beef but my mom sure didn't know how to cook a good steak. I actually learned to cook a good steak from my ex hubby and have an older son who perfected the technique enough to keep a small country cafe crowded with folks coming from large towns looking for a good steak. They both preferred charcoal grilling.
I season my steak with kosher salt, ground pepper and garlic granules. They have already discussed cooking times and methods. If I'm not grilling I heat a cast iron skillet until it is very hot over med high heat. I lightly oil it and add my seasoned meat, brown one side then the other, turn the heat down to low, put the lid on and cook to desired level of doneness. I remove it from heat, cover it and let it rest before serving, if grilling I wrap it in aluminum foil. Sometimes I finish it in the oven rather than on top of the stove. I have used rubs, marinades etc but this simple method has never failed me and the rubs etc while good have never been a big improvement.
Salt it before cooking, not while cooking.
Sear it good on both side on higher temp, turning only one time.
Cover and let it rest before serving.
Those are the key points. BTW, you can use the same method for pork steaks, chops or loin slices and for boneless chicken breast. I usually add some herbs (thyme, rosemary) to them before cooking.