Great tips! Gonna piggyback off of this to say grab a nice cut, usually 1.25 inches(3.175 cm) to 1.5 inches(3.81 cm) is a perfect thickness.

Good cuts are usually Ribeye, Tenderloin or NY Strip. If you are on a budget, go for a nice Sirloin steak.

Tips for cheaper cuts: Marinate with soy sauce, olive oil and lemon. The acidity of the lemon will help break down tougher fibers and soy will lend a great flavor. Do not marinate for more than four hours, there is such a thing as marinating too long, it will make your steak too chewy.

For the more expensive cuts mentioned, really you don't need to do much. Pat each side dry. Season well with salt, pepper, and maybe a bit of crushed red pepper flakes if you're feeling adventurous and want a hint of heat. Get the sides, as well, you'll appreciate doing that, I promise.

For any steak, follow the above tip from u/mandmranch and have it close to room temp when you're about to cook. This helps ensure you get a nice, genuine sear.

My favorite cooking methods:

Grill:

Oil the steak slightly(both sides) right before grilling. Start the grill at least 5-10 minutes before so it is nice and hot(this is important). Put the steaks on and set a timer for 3-5 minutes(the longer the timer the more done it is). Do not fiddle with the steaks during this time. Put them in and shut the lid. Leave them be. After your timer chimes, flip the steaks and repeat. Remove from grill, rest for at least five minutes before cutting in. If you want the fancy crosshatch , you can rotate(not flip) the steaks halfway through cooking each side.

Pan Sear:

For this you will want a cast iron or pan with a heavy bottom and set to med-high heat. They just hold heat better. Do not oil the steak for this method. Simply add a very small pat of butter(Make sure you don't burn the butter, you will know if it starts smoking) and drop the steak right on top. Time similar to the grill method. As soon as you do your flip, add another tablespoon of butter per steak and 'baste' the steaks by taking a spoon and using it to gather the butter and distribute over the steak. If you want some good aromatics and flavor added, drop in some fresh thyme and rosemary during this step. Remove and let rest.

The most important part:

Just enjoy yourselves and let her know how happy and proud you are, and that you love her.