So...you've probably been wearing your bra wrong your whole life
There are more than a few things you don't need the instructions for: cereal, shampoo and until today...bras.
But as it turns out, you've probably been doing it wrong your entire life. As it turns out, you should first be trying it to the loosest hook, properly place your breasts into the cup and voila! Put the real kicker is: tighten the straps every other month. Not every time you're wearing a low-cut top, but every other month and it should fit like a glove.
The older you get, the more you realise the importance of investing in a good bra and getting fitted every so often, because chances are, your bra size is bigger than you think.