Order it up when you have a meal on the ship (8)
I believe the answer is:
tidiness
'order' is the definition.
(tidiness is a kind of order)
'have a meal on the ship' is the wordplay.
'have a meal' becomes 'dine' (I've seen this in another clue).
'on' means one lot of letters goes inside another.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'ship' becomes 'iss' (I can't justify this - if you can you should believe this answer much more).
't'+'iss'='tiss'
'dine' placed inside 'tiss' is 'TIDINESS'.
'it up when you' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tidiness that I've seen before include "Insisted on neatness." , "Quality of neatness and orderliness" , "sense of order" , "good order" , "Orderly quality" .)