According to my plastic surgeon ( who did my breast reduction operation) the bust peak/nipple is supposed to sit at the mid-point between shoulders and elbows. Yet for many, this is not how it goes. Yours may sit higher or lower (anyone with a large bust will find theirs is likely to sit lower).
So how does where your bust sit naturally influence what you wear? Not only is there the height of breasts, but also if they are more narrow (sit close together) or wider (sit further apart on your chest).
What's the Impact of Breast Placement on Clothing Choices?
High Breasts
This can happen if you have a short decolletage area and most often means that you'll find the straps on clothes are too long. You will need to take lots of clothes up from the shoulders and you may find that bust darts are too low for you. High breasts can make you look a little broader through the shoulder area.
Low Breasts
This is very common as a larger bust will sit lower (there's just no getting around it). You may find bust darts are too high and most empire seams sit on the bust instead of under it (which looks terrible and isn't comfortable).
Low breasts will also make your waist proportionally shorter, a good bra that lifts them as high as comfortably possible will improve this, but you may decide you don't want to do any waist emphasis even if your body shape information calls for it so as not to draw attention to your shorter waist. Instead, just make sure clothes are fitted through the waist, rather than highlighting it with horizontals such as belts.
Wide-Set Breasts
Breasts that sit wider will make your torso appear larger as they often extend past the sides of your body. You will find that lower necklines wraps and V necks can work well as you have the space for them and don't look like you have as much cleavage as someone who has narrower set breasts.
You may find it harder to find fitted garments from woven fabrics to fit as well, such as tailored jackets and button-up shirts, as your breasts may pull at the fabric. You are also likely to have horizontal creases appear in knit tops too as your wider set breasts stretch the fabric across your busts.
Narrow Set Breasts
Breasts that sit close together will form a more obvious cleavage and can appear larger because of this. You will find that lower v necks will show off your cleavage and anything particularly deep will be hard to wear without worrying that your breasts may "fall out".
As you can see here (above left) I have more narrow set breasts and so can look too "booby" (as I call it) in any sort of V neck cut as my cleavage becomes very obvious. This is one reason why I prefer a scoop neck that doesn't expose my cleavage in this way (above right).
Large Breasts
A very large bust is most likely to sit wider than your torso (like mine used to do pre-breast-reduction - see below) and make you look larger overall. Wearing loose clothing tends to make you look big all over, rather than just having a very large bust. 
You need clothes that come back in at the waist to stop the volume of your tops making you look big overall.
Soft fabrics that glide over your curves that can be tucked or are designed to come back in at the waist or under the bust are ideal.
Shallow vs Projected Shape
This can completely change how your bust looks and will fit into clothing.
Shallow breasts have their tissue spread out over a wider area and will not appear as large (forwards) as Projected breasts, which have a narrower surface area on your chest, but project forwards. Think about Shallow breasts being a dinner plate, and Projected breasts being a drinking glass. Both may fit the same bra cup size, but are shaped very differently. A shallow breast will fit more easily into a woven/button up garments, whilst a projected breast will find fitting these kinds of garments very tricky.
Bra Fit
You will also discover that different brands of bras fit differently and are made for different shapes. I highly recommend you go down the rabbit whole of A Bra that Fits which has a plethora of resources to help you discover what kind of breasts you have, your best bra size, and the brands that will work ideally for you.
How to Flatter Smaller Breasts
The Scale of Necklaces Relating To Your Bust Size
Your Ultimate Guide to 17 Necklines and Which to Choose to Flatter Your Features
How to Make Your Small Bust Fuller
8 Tips on What To Wear When You Have a Flat Chest
