Likewise - I jumped from 54% to 96!
Second run was elite, taking a sniper m101 sniper and silenced pdr - though I tried to use the war hound as little as possible, only for major targets like the helis, and to get through the timed run inside
Went for accuracy and hshots, speed, and marking targets for team, and sensors - I think like on multiplayer you get better scores if you play a teamgame....
Also, I did see a note on one of the scrolling messages on the loading screen that set something like finishing a fight as soon as possible gets you a better score - hence speedier runs get better scores overall. Don't dawdle in fights, cowering behind cover all the time inactively. Mark targets, pop up and shoot, and keep pushing forward. When you get to a new area, survey it, work out a strategy and execute swiftly. Seems to have worked for me on all others so far.
I'm also half way through deep fire using the methods above, needing a score boost for that, so we'll see what happens.
Dying doesn't seem to affect you score, or only marginally if so.
Last edited by UltimateTT66; 09-14-2012 at 12:10 PM.