For years, I wore a sort of uniform of bright colored crew-necked cotton T-shirts and plain blue jeans with tennis shoes. I switched to turtlenecked or mock turtlenecked sweaters in winter. It was comfortable and wash-and-wear. About two years ago, I lost an enormous amount of weight. About the same time, I decided to get serious about my career goals, and the T-shirts and high-waisted jeans had to go. I've had to completely banish them from my wardrobe, otherwise I go right back to them. I made figuring out clothing an interest -- I read webpages with fashion slideshows and advice, found things I could live with and then found a store that pretty consistently stocks things I both like and can afford. Since then, I've found other stores that carry similar things, but I pretty much stick to that one chain. (If JC Penney's ever changes their buying strategy, I'm in trouble. )
Among the things I've discovered is that, if they fit properly, dress slacks are actually incredibly comfortable. I still reach for jeans first out of habit, but I don't mind wearing other pants now. I've also discovered that I don't need a special occasion to wear a dress and that they are also very comfortable -- again, if they fit properly. I kept the turtlenecks for winter but lost the crewnecks. I've discovered that I don't like sleeves that are too short -- funny I never noticed that with the Ts -- or too long. I like three-quarter length sleeves. If sleeves are long, I'll either push them up to my elbows or roll them up. I don't like fancy things with fussy trims. I prefer smooth and pretty classic styles.