Very early way to keep trees: get your priorities right (5,6,5)
I believe the answer is:
first things first
'keep trees get your priorities right' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'very early way' is the wordplay.
I cannot really see how this works, but
'early' could be 'first' (associated in meaning) and 'first' is found in the answer.
'way' could be 'st' (abbreviation for street) and 'st' is found within the answer.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Another definition for first things first that I've seen is " Start at the beginning".)