1- CARRY A FREAKING BOW! If you are proficient with them, there is no reason not to! It's unbelieveable how often players (even veteran players!) forget about this! Then a flying enemy comes along and their uber-warriors can't do anything.
2- Carry backup weapons. Because you'll eventually be disarmed or have your weapon destroyed. Have a back up. It doesn't have to be as good as your main weapon, but it has to be good enough to keep you alive until you find a better one.
3- Remember: there are no aggro mechanics in Pathfinder. If you want your enemies to focus on you instead of the squishy wizard, you have to give them a reason to! Most often, this reason is raw damage output, but there are other ways.
4- Don't underestimate consumables. I know potions/scrolls are wasted after you use them, but sometimes, they're all you need to get through that one encounter/challenge.
5- Don't overspecialize. Be awesome at whatever it is that you want to be awesome, but don't do it at the cost of being inneffective at everything else. Sometimes, your usual course of action will not be a viable solution.
6- Always try and get as much information about your next challenge/enemies/puzzles/quest/etc as you can. Knowing is half the battle.
7- Carry wands of Cure Light Wounds and wands of Lesser Restoration. They'll save your life more often than your party. lol.
8- Put skill ranks in Perception. Even if your Wis score is not very good and Perception is not one of your class skills. You'll be rolling Perception skill checks more often than any other, so you might as well invest in it. It'll probably save your life at some point.
9- Carry a scroll of Daylight. Seriously. Sooner or later your GM will throw a vampire or shadow demon in your way. They all do. (Admittedly, this advice is more based on personal trauma and paranoia than game analysis)
10- Last but not least: Have fun! That should be your ultimate goal with any game, after all.