The grand-daddy of all mantras: wear all the protective gear at all times. Even if it is 105F and you are just going a mile to the store. It is pretty much agreed that leather offers the best overall protection but nothing beats textile for versatility and features. I have covered some of my gear in previous posts, and will be filling in the missing bits soon.
Every day is an adventure!
This is a personal mantra of mine and is a reminder that some days just aren't going to go the way I expect. My attitude on those days is the most important factor in determining how well I make it through. Every single day offers the possibility to learn something new, meet a new friend, try new food, look at old haunts with new eyes, or just acknowledge the grandeur of the world around you.
The single best overall line to take through corners is to start from the outside edge of your lane, pass through the apex of the turn near the inside edge of your lane, and end up on near the outside edge again. This path maximizes visibility -- both yours of oncoming traffic and corner conditions, and theirs in seeing you. Coupling this with smooth braking before the turn, and a gradual roll on of throttle through the turn, and you are on your way to corner mastery.
The bike goes where you look.
I cannot count the number of times I have fixated on a pothole or crack in the road ahead, and ridden right into it. It takes conscious effort to note a hazard and then fixate my gaze at a distant point that takes me past it safely. This is also the reason the MSF classes tell you to rotate your head as far as it will go when making tight turns. If you fixate on the middle of the curve, you will run into it. Looking at your exit point will help you complete the turn.
Tight on the bottom, loose on top.
This was actually the first piece of advice after ATGATT that really improved my riding. It means simply to use the lower half of your body to grab the motorcycle, and keep the upper half of your body relaxed. I used to ride the exact opposite way and quickly wore out my arms as they bore my weight. If your arms are rigid, every single bump will jar your whole body. I have almost been thrown off the bike hitting a large unexpected pothole with stiff arms. Now I try to support my weight with my legs and abdominal muscles and ride much more smoothly. This is another one for the application of conscious effort. Periodically during my rides I try to take a moment to wiggle my fingers, check on the stiffness of my arms and shoulders, and grab firmly but gently with my lower half.
As with all advice -- take everything with a grain of salt and a pound of personal experience. The best advice of all is simply to remain open minded and continuously look to improve your riding skill. And wear the gear!