It gives a preview of what's in store for you (4,6)
I believe the answer is:
shop window
'it gives a preview of what's' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'store for you' is the wordplay.
'store' becomes 'shop' (synonyms).
'for you' becomes 'window' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'shop'+'window'='SHOP-WINDOW'
'in' is the link.
Can you help me to learn more?
(Another definition for shop window that I've seen is " Where things are shown to advantage".)