"Fancy" Cocktail Bar & Other Spot Recommendations Please! (NW/W/Central Houston)

I have a friend coming to visit from overseas and we are looking for a bar with a good atmosphere and preferably a dress code! Not sure where we will be staying yet so suggestions for anywhere in Houston are more than welcome. We are both 24 and have only ever really been to normal bars. We are looking for a new fun experience!

I am a native Houstonian but I have literally no knowledge of the city :^) So if you know any other fun things to do, feel free to drop them here! It's more of a romantic vibe but I am more than open to any suggestions. We plan on doing the museums, the zoo, and possibly NASA but that's all I've got. Help!