It is a combination of both, as well as post processing (we do it the halite tool and custom tools in Fusion).
You might try some small, but bright lights that only affect reflection. Bump maps with small nicks. Overall noise bump maps with a big scale, bump low amplitude to get some variance. Variance in the reflection gloss channel can look nice as well.
Then you bloom these highlights out in the post, using possibly only the reflection channel to drive the blooms.
It is all very scene dependent though. Post pics for better feedback.