how can i get more steering by changing the setup? what should i change?

There are a number of things you can change. But first, why don't you give us an idea of what set-up you're using that isn't giving you the results you want. Everyone can make a better suggestion that way.

diffs: 7000 front and rear, 15000 center, shocks: 40 oil front and rear springs: yellow in the rear silver in the front. stock positions and 0 camber in the rear, little toe it front and rear, o.5 camber in in the front

I'd say keep the diffs that way, go to 1degree rear toe-in, 2-3 degrees toe-out in front, if the hellfire has castor clips, move the clips to the front of the a-arm. Then use your radio to set the servo EPA to the max travel.

Report back to us if it's still not enough. It may just be a slow servo

you can also take youre tie rod and move it to the rear hole on the steering ackerman.

Yes, if it has Ackerman, put it in the rear-most hole(when looking at it from the top, and with it pointed forward) And try thinner diff fluid if you want front and rear for more off-power steering, or make it thicker for more on-power steering, depending if your problem lays within entering turns or exiting.

And do you have a servo with at least a .10 sec transition time? Because if not, there's your problem

Here's my current HFSS setup in a nutshell

diffs
front - 7000wt
center - 15000wt
rear - 5000wt

shocks
front - 40wt/pink springs/stock pistons, tops are mounted upper row, second hole from center. bottoms are mounted on outer hole.
rear - 35 wt/yellow springs/stock pistons, tops are mounted upper row, third hole from center. bottoms are mounted on middle hole.

ackerman mounts are full forward.

roll center links are stock settings for HFSS.

no sway bar up front
gold sway bar in rear, mounted 4 mm in on outer rods.

rear hubs are mounted full forward.

Sorry to jack your post but, could someone explain the terms above and, why they make a difference? Like what is the Ackerman and, why does it make it steer more if in the "rear holes". Also what does moving the rear hubs full forward do/affect?

I have the Hitec HS-985mg servo for steering in my HF and, it seems to lack steering a little.