First and foremost, DO hire a porter! Carrying stuff uphill at altitude is hard. We ended up paying for a porter on day 2 and 3, it was well worth it.
DO train in advance! And practice carrying a heavy backpack.
DO take clothes made from synthetic quick-dry material. I wore a cotton long sleeve top on the first day; it got drenched in sweat and didn’t dry for 3 days.
DON’T wear shorts or ¾ pants; mosquitoes annihilated everyone who wore shorts on our trek. It was ugly. And itchy, I imagine.
DO make sure the music on your smart phone is available offline. If you plan on listening to music to get you through the difficult uphill stretches you may find yourself in a pickle if your Spotify, iTunes or Google Play doesn’t work without internet.
DON’T overdo it on the snacks. You are so well fed on the trek that you will just end up carrying them around.
DO bring earplugs. I swear by earplugs in hostels but naively thought we would be fine without them on the trail. Barking dogs and heavy snorers proved me wrong.
DO take a wireless charging pack for phones and cameras. Or make sure everything is fully charged.
DO take dry shampoo ladies. I wish I had, never felt so gross in my life!
DO try and stay an extra night in Aguas Caliente to visit Machu Picchu again the next day (showered and well rested) if you can spare the time. I was so tired having been up since 3:30am that I really didn’t appreciate or take it in.