Updated July 25, 2023
First and foremost, bring comfortable walking shoes. You'll do a lot of walking within and among casinos and between rooms and parking garages. High heels can really take a toll.
An if you're like us, you'll want to walk. Eating out three or even two meals a day, you gotta do something to work off all those calories and carbs. This used to be truer, when those paragons of over-indulgence, buffets, were more common, but this is still the Excess Capital of the World.
A close second is to stay hydrated. The dry heat means you often won’t even know you’re perspiring, but you are, so remember to drink plenty of water, especially if you’re indulging in excess alcohol or drinking a lot caffeinated beverages, both or which are diuretics that exacerbate dehydration.
Use sunblock with UVA and UVB screening properties, even on a cloudy day. In fact, especially on a cloudy day, when the UV rays are still hitting you, but you might not feel the sun. Don't let sunburn ruin your vacation (or your skin).
Be especially cautious if you're outside for any length of time in temperatures of 100 degrees or higher.
Carry a sweater/jacket/wrap with you in the hot summer months. You certainly won’t need it when you’re outside, but the often arctic-esque indoor temperatures and the constant fluctuations you’ll put your body through can result in horrible summer colds. Make sure you can wrap up when you enter a casino or restaurant. Otherwise, you'll be in danger of freezing to death in Las Vegas when it's 110 out.
Actually, you need to to be prepared for all the different weather that happens here throughout the year: high heat, low humidity, and flash flooding in the summer; cold and some snow in the winter; high winds year-round.
Beyond that, it's Vegas, baby! Anything goes.