We just did a fun project at our Sewing Guild. We did the T-Shirt Makeover by Pamela's Patterns. You take a x-lg t-shirt and give it some shape by re-cutting the sleeves, tapering the sides to give it a "essence of waist" and also tapered the hemline up a bit in the hip area to make it more flattering. I learned a lot about fitting my narrow shoulders and then extending the pattern under the arm to fit my wider body.
I took that knowledge and made another knit shirt with a different neckline, etc. from scratch using another of her patterns. Knits are so forgiving, I'm having a ball making some tops that actually fit. I haven't even bought too many of the current knit tops as they usually are too tight in the bust area if I get them to fit right in the upper chest. Next thing I know, I'll be trying my hand at tencel and slinky -- I hear they can be a bit of a challenge.