So many mistakes I have made! For example:
1. Not drinking enough water. Lesson learned: Drink lustily, and before you are thirsty!
2. Not eating enough. Lesson learned: Nibble frequently!
3. Being cavalier about the sun. Lesson learned: Cover up! Sunburns are no fun.
4. Imagining that stock gearing would be fine. Lesson learned: Install the granniest granny gear your bike will accept. If you find yourself going uphill for 20 miles on a 15% grade, you will be glad.
5. Going too far on the first day. Lesson learned: Take it easy, and give your body time to acclimatize to the rigours of touring.
6. Forgetting to smell the flowers. Lesson learned: Slow down, and enjoy yourself. It's a tour, not a marathon.