Good soldiers come in first thing with tea (4,4)
I believe the answer is:
earl grey
'tea' is the definition.
(Earl Grey is a type of tea)
'good soldiers come in first thing' is the wordplay.
'good' becomes 'g' (abbreviation).
'soldiers' becomes 'RE' (Royal Engineers).
'come in' is an insertion indicator.
'first thing' becomes 'early'.
'g'+'re'='gre'
'gre' going into 'early' is 'EARL GREY'.
'with' acts as a link.
(Other definitions for earl grey that I've seen before include "Kind of China tea" , "Flavoured kind of tea" , "Noble" , "leaves a lot to be desired?" , "brew" .)