Desire comes before soldiers shine (6)
I believe the answer is:
lustre
'shine' is the definition.
(lustre is a kind of shine)
'desire comes before soldiers' is the wordplay.
'desire' becomes 'lust' (I've seen this before).
'comes before' means one lot of letters go next to another.
'soldiers' becomes 're' (Royal Engineers**).
'lust'+'re'='LUSTRE'
(Other definitions for lustre that I've seen before include "Gloss - type of pottery" , "Gloss, sheen" , "Sheen - glaze" , "Brilliant quality in a material, porcelain, etc" , "Result (anag) -- gloss" .)