Off the shoulder tops and dresses are in at the moment.  You can wear the tops with pretty much anything, there are a lot of cool looser styles around as well as tighter ones that could work under dungarees.   To breast feed the neck can be easily pulled down (dress) or a top can be pulled up (worn with lycra boob tube underneath).  

I recently posted a photo of me wearing The Honey dress from the AG Jeans Alexa Chung collection.  Its a really cool dress, loose fitting and flattering.  I wore it with trainers but i expect i will wear it with sandals and wooden heels to.

Showing your shoulders off can be a nice and flattering way of exposing a bit of skin and feeling summery without feeling to naked/ exposed. 

ASOS £20 / Zara £25.99 / ASOS £30 / H&M £29.99 / Glamorous £22 / Glamorous £22