Aware of current trends, lit up? (8,2)
I believe the answer is:
switched on
I believe this clue is a double definition.
'aware of current trends' is the first definition.
(switched on can mean aware or informed)
'lit up?' is the second definition.
(as in lights switched on)
(Other definitions for switched on that I've seen before include "Aware" , "with electricity supply?" , "Now listening to Radio 4, say" , "Illuminated" , "lights working?" .)