I can't believe people are saying the only way to get a gold shield is boosting. Explains a lot about the stuff I come across in-game if that's the backwards mentality of the people who play it.
It's a miserable experience, and your K/D WILL suffer but it's doable. Think I ended up with a 0.42 K/D after just under 300 kills to get it gold and to max level.
Ghost / flack jacket
Extreme conditioning / tac mask
My worst enemy was people using tac mask.
HC was good for one bash kills, but a nightmare as it only takes a stray bullet hitting your elbow to kill you. I did some in core TDM when the kiddies were off as they were pretty clueless so easy prey.
I'm one bloodthirsty kill with the crossbow from Diamond specials. I finally finished the Riot Shield, and as others have said, it's not that bad. I played HC TDM, and went with combat axes & shock charges. Sure, I wasn't improving my K/D, but I didn't lose much ground either. Just stay in close quarters parts of the map.
Any suggestions for getting that crossbow bloodthirsty would be appreciated!