If you try to do the leaps of faith, you sometimes have just a small platform to jump from.
This makes timing a jump or especially a sprint jump quite difficult.
I really had trouble to do the leap of faith in the acheronian ruins.
After having failed too many times I put a macro on one of my mouse buttons doing W-SPACE.
I used these timings:
W down
0.02 s delay
SPACE down
0.159 s delay
SPACE up
0.16 s delay
W up
I prefered to press SHIFT manually to be able to do a sprint jump, if needed, or just a "normal" jump.