1) If you can't afford expensive sheets, buy cheaper ones in "sateen". They feel just as nice! I found a king set for $20 at a discount store and love love Love them!
2) If you don't feel good on the inside, make yourself look good on the outside. It cheers you up psychologically and also makes you feel less sick (if you are under the weather).
3) Never keep a compliment to yourself. No matter who it is, if I see, say, a pair of earrings that I like, I make sure to share my appreciation with the person wearing them.
4) If it isn't worth divorcing over, then it isn't worth arguing over. I learned this little bit of wisdom a LONG time ago, but @mommyneedsmeds put it perectly into those words.
5) Your child will never be this exact age again. Cherish each and every moment, and record those memories!!!
6) Which brings me to the next point: go ahead and splurge on that good camera. All things considered, you probably end up spending more on fast food, coffee, or manicures each year than the price of a nice DSLR. Cut out a few luxuries and BUY THAT CAMERA!
7) Say "I love you" to everyone you love, every time you see or talk to them. It makes you feel good, it makes them feel good, and you never know if/when you might have the chance again.
What other things would you add to this list?