Book with sticker not good to waste (4)
I believe the answer is:
blue
'waste' is the definition.
(blue can mean to squander or waste)
'book with sticker not good' is the wordplay.
'book with' becomes 'b' (abbreviation for book. I am not sure about the 'with' bit.).
'sticker' becomes 'glue' (I've seen this in another clue).
'not' is a deletion indicator.
'good' becomes 'g' (abbreviation).
'glue' with 'g' taken out is 'lue'.
'b'+'lue'='BLUE'
'to' is the link.
Can you help me to learn more?
(Other definitions for blue that I've seen before include "This could be royal or navy" , "Sunny sky or low spirits" , "Dismal" , "Dispirited in cerulean way" , "Sky-coloured" .)