Light packing is right packing. Trust moi, you do NOT want to be schlepping your giant or super-heavy bags all across New York.
Start with 2 good suitcases, a super-light hardback like this one with wheels that spin, and one that is both big enough to carry your laptop, Kindle, gossip rags and your gorgeous Mona B crossbody bag or tote and small enough to fit under an airplane seat. And don't forget these Bose earbuds. Simply awesome. What else goes in these carryons? As always, I cannot recommend Buckle tanks enough. They are so versatile, can be worn under EVERYTHING, even to work out at the hotel gym and to sleep in. Always bring your onesie (sweats or comfies & a hoodie). You never know when you might need to head downstairs for coffee before you're ready to go out for the day and be seen by other humans.
You're going to walk A LOT around NYC, probably more steps than you ever planned, so the good news is, you don't have to dress up too much for Broadway shows anymore, but PLEASE dress up a bit. Think of it like you're heading out on a casual date: a pretty top like these from Gimmicks and dressy jeans. A shorts/skirt combo with a sparkly top? Perfect!
When you are selecting specific pieces to pack, first choose one color palette to build your clothing choices around. You can tell from this pic of my scarves fastened on outside of suitcase (another key space-saver!) that I went with orangy-gold-brown as my base. It made packing so much simpler. Also, some good news, ladies: no reason to bring heels! Wear some sparkly flats or Ugg sandals at night (these from Madden Girl are adorbz!) or glittery Keds during the day to glam up your outfits. Plan to wear the same pants/top to fly in and out of the city, and just wear a different Buckle tank under it. I am obsessed with the faux-leather wine-colored pants from Spanx and wear them EVERYWHERE, especially when I travel. They're high-waisted, and if you wear the Buckle tanks I recommend, the waist won't roll down. I promise. (As far as what makeup to bring, please read my post on Travelin' Beauty. And check back in to my blog for specifics on what other products must go in to your beauty bag.) Now! You're in the city (having flown in to Newark. Easiest and fastest). You're going to walk everywhere, all day. In a walk-intensive city, be sure to always keep some hand lotion (or stop in to the closest Duane Reede or CVS) like this Neutrogena hand cream. They don't advertise it as such, but it's an awesome blister-preventer.
Don't forget to pack wrinkle releaser, and this just happened to me in NYC, but if you do, don't fret. Get your wrinkled clothes a bit damp in the shower. Don't steam them - you need the bathroom to get ready - simply lightly spray the shower directly on them and let them hang for a bit. If they're still damp when it's time to wear them, use the hotel's blowdryer.
Where to go in the city? You'll likely spend time in midtown, so plan to eat lunch at Cock & Bull, and get your reservation for Butter NOW & enjoy yourself a nice meal. Hint: share an entree. And by entree I mean the steak.
As far as other must-do & see in the city, a few other blogs like the 100 NYC Must-Do’s from a cool site about RV’ing (Yeah! Trust me!), plus this and this one have nailed it, so I'll just mention the Village. You GOTTA go to Murray's Cheese Bar and the speakeasy where the term "86" was invented. And, for a guidebook, nothing beats the Lonely Planet.
Finally, please remember to avoid 45th Street in Midtown at all costs in the hours before most Broadway shows start. You will WALK it faster than your Uber can drive it.
Now go forth. Be Veracious.