What's something you guys do that makes you feel smarter just by doing it? I'm not talking about sludging through school every day. I mean, reading wiki articles for fun, or doing a Sudoku, or fixing up your car by yourself.
I like reading the newspaper and watching CNN from time to time. Being up to date on current events makes me feel smarter.
Always trying to learn more behind the things you like and how things work and always try to expose yourself to new things. Work where you have to think everything out can only help build a habit of planning well, too. And of course, never underestimate discussing those earlier likes with other people- especially ones who you respect and respect you. Good things generally come from those discussions.
Civ V makes me feel smart when I scam world leaders out of their resources. Airglasses are pretty high on my list of things I do when I'm feeling like I just did something clever.
Engaging in deep conversations with my Engineering/Physics major friends. At least, it makes me feel smarter, lol. Catching up with current events also makes me feel smart, it's just a matter of where it comes from that justifies its content for me.