1. Think about how much water you might need. Bring double that amount.
2. Think about how much time you need to complete your trek. Multiply that by at least 150%.
3. Figure out how hard you think it might be. Overestimate that significantly.
4. Think about all the stuff that you might possibly need beforehand, locate it, pack it, and then leave half of it behind. If you don't, you either won't make it at all, or you'll end up dumping half your supplies on the side of the trail.
5. Bring a lot of lightweight layers of clothing for all types of weather, even for a short distance on a sunny day! Wear a hat. Wear sunscreen.
6. Eat a lot the night before, so that you don't need to bring so much food. It's all about the weight you're carrying.
7. The more planning you do, the safer you'll be and the more you'll get out of it. Unexpected weather changes are killers, or at the very least you'll end up lost and stranded.
8. Bring a small weatherproof camera. You'll want it! (No DSLR's. iPhones on silent are acceptable.) Bring a friend or at least some pen and paper.
9. Don't run up the mountain, you'll miss a lot of the experience. You'll also likely fall and get hurt. Additionally, do remember to give large carnivorous animals plenty of space!
10. Take something away from the experience. Learn from it. (This is really the number one rule. The more practical advice just happens to be first.) Don't do it just to impress others. Take something away from it. Likely what you learn won't be what you expected to learn.
~Nick Whittemore (November 21, 2013)
Obviously there are hundreds of other good pieces of advice. These are just some things that I've learned and ever since tried to stick with, and they've worked for me.
