If you shoot uphill, then aim low.
If you shoot downhill, also aim low.
How much depends on your bullet drop values at the specific target range multiplied by an angle quotient.
For example:
Let's assume your 30-06 drops 9.3 inches at 200 yards.
You are shooting 10 degrees downhill (or uphill in fact), then the 10 degrees quotient is 0.015 (see table below).
You will compensate by 9.3*0.015=0.14 inches low.
You will find drop values in your cartridge ballistic data.
Angle quotient are like so:
0 degrees=0
5 degrees=0.004
10 degrees=0.015
15 degrees=0.034
20 degrees=0.060
25 degrees=0.094
30 degrees=0.134
35 degrees=0.181
40 degrees=0.235
45 degrees=0.293
Or use ballistic software if you don't like math.