Backpacking Lessons

Foot care is important, especially when feet get wet. Some people use some sort of foot lotion.
Some footwear can be improved by gaiters, snowproofing treatment for wet conditions, and re-soling.
"Trail legs" supposedly get stronger over the course of a multi-day backpackpacking trip.
Not all backpacks are water-resistant
Pack savory and salty food. Potato chips, salty popcorn, cheese puffs...
Ice in water bottles
Trekking poles for knees downhill in difficult terrain
Guthook app (since renamed to FarOut). Other potentially useful apps include AllTrails and Gaia GPS.
Ursacks for places where they are a permitted alternative to bear cans
Check how long it typically takes for you to get ready in the morning, in case you need to know that for e.g. beating the tides
Print out song lyrics and sing them while hiking (my choice: American Pie by Don McLean)
Tell a friend where you're going and when you should get out
Consider adjusting smartphone photography settings. For example, Samsung's "Scene Optimizer" seems to work well for pets, but overly saturates skies.