See about green colour at last for deck (8)
I believe the answer is:
decorate
'deck' is the definition.
(I know that deck is a kind of decorate)
'see about green colour at last' is the wordplay.
'see' becomes 'date' (synonyms).
'about' means one lot of letters goes inside another.
'green' becomes 'eco' (eco-friendly).
'at last' indicates one should take the final letters.
The final letter of 'colour' is 'r'.
'eco'+'r'='ecor'
'date' going around 'ecor' is 'DECORATE'.
'for' is the link.
(Other definitions for decorate that I've seen before include "Honour" , "Add ornament, colour, etc." , "Improve the look of" , "'Adorn, beautify (8)'" , "'Adorn, embellish (8)'" .)