One of my favorite style-isms is the concept of high/low. Pairing high priced items with low. One idea: t-shirt with cardigan. (Not to say t-shirts are always low-priced!) I think this gives a nice youthful vibe.
Delias has some great t-shirts. And they are really soft.
Paris Life Tee, delias.com, $24.50.Madeline Two Straight Lines Tee, delias.com, $24.50 (save $10 when you buy 2).Etsy is a great place to find shirts that no one else is likely to have. Like this one by Pretty Raccoon, $31.Or this one, by discobelly, $25. (It's maternity.)
And now for the cardigan...
I like this one from Old Navy, $24.50, machine wash.
***Old Navy also had a zebra-print cardigan in their store the other day, but I couldn't find it online. I think it would look amazing with one of these t-shirts.Or try this beautifully detailed Ruffle Cardigan by JCrew, $88, dry clean.