How to make clothing that flatters your figure:
1) Find out what flatters your figure. Older books are often better about being blunt about this. Newer style books will say, "oh just wear whatever". Don't. You know this. Another good way to see what flatters your figure and face - photographs. An old photo of a blouse I made ages ago has inspired me to try a whole new neckline. Likewise, the "almost good" isn't good enough for you to make with your own little hands.
2) Get ideas. What you don't want to do is just look at whatever is in the mall and say, "woe is me. Batwings are in and they make me look like a linebacker". You'll end up finding a less-linebackery batwing... but why not avoid it altogether by finding something that truly flatters YOU? I like scanning vintage patterns for this - you can get ideas that aren't currently en vogue and use those to your advantage. Yes, something that was all the rage five years ago will look dated today - but something all the rage 20 years ago? You could just be ahead of the style.
3) Be honest. If you know perfectly well that you can't wear a certain shade, don't. Buy it in a throw pillow for your couch. Buy a shirt for your beloved. Just don't put it on your body.
4) Have some fun. But what about that color that *does* look amazing on you? Why not pair it with that neckline that hasn't been seen for 40 years and do something amazing? Buttons and trim are part of play. For instance, I get mad compliments on that blue and red blouse - I wouldn't get half so many if I hadn't said, "what the heck - it'll be bright, but I know those colors rock on me" and gone for broke. Do eet.
5) Learn a basic pattern, then play with it. If you look at the vintage patterns, you'll often see a basic shell dressed up or down or sideways with different collars. The bodice is the same - the collars make all the difference. Or the sleeve. If you don't have figure issues that prevent sleeve play, by all means do something with your sleeves. Sleeves are expensive to mess with in terms of time, so you won't see much ready-to-wear with interesting details... you could make something amazing. (Vintage patterns are great for sleeve inspiration).
6) Play up your best features, and change them around if you can. Bright eyes? Velvet skin? A throat that makes swans envious? Show them off. This *can* be sexy, but doesn't have to be. It will be beautiful. Be comfortable in your beauty.
7) Play with texture. I know certain textures are my friends and some are ... not as friendly. Lace and tweed and leather and knits... they love me. I love them back. Why not wear lace with tweed? I can pull it off. Maybe you look amazing in the most pulled together, controlled stuff... take it to the max.
Above all - keep your eyes open to the "yeses" and start plotting the garments of your dreams.