Never underestimate the worth of a good tailor. It is not expensive and it is crucial if you are an hourglass in a pencil shaped world 
I’ve got bust and booty but a small waist. I buy my clothes to fit my chest and my hips and then (if necessary) take them to the tailor to have them nipped in at the waist and shortened (if necessary).
When you go shopping wear (or bring) the shoes that you intend to wear with the outfit. There’s nothing worse than buying pants that were the perfect length with the sneakers you were shopping in but too short when you put on your shoes.
There’s no such thing as “it’s fine” or “it will do”. If you don’t love it, leave it there - that isn’t the only pair of pants/skirt/shirt in the world.
Also, don’t be afraid to buy a piece that looks good on you in every color they have. For example, I have the same pair of slacks in black, brown, khaki, and olive green and, I have the same V Neck in pink, powder blue, black, olive green, and brown. So, there’s a ton of combinations right there and I always feel good because I know that those pieces look good on me. And, I follow that same pattern with everything - T-shirts, jeans, bras - everything. (yes, my closets are overflowing - why do you ask
)
I also buy jeans I like in all three lengths - petite for sneakers, medium for shoes, and tall for my high heels - but if you don’t like heels then you might not need to do that.
Don’t avoid the Juniors department - they have great stuff. I don’t care that I’m 39 - you’ll pry my Happy Bunny t-shirts from my cold, dead hands.
The most important thing is to try to take someone you really trust with you. It’s not fun to hear your best friend say “No. That is hideous on you” especially when you are kind of digging it, but in the end it’s worth it.
Sorry for the long post - I hope at least some of it helps 