I failed miserably at least twice before successfully making pemmican.
Here's a couple things I learned:
To render beef fat requires patience.  First cut the fat up into small
chunks.  I remember someone suggesting having the butcher grind it; this
seems like a good idea to me, but I haven't tried it.  (They look at me SO
strangely when I ask for the fat, I'm afraid if I asked them to grind it
they'd call the loony bin.)  Second, cook on VERY low heat for a VERY long
time.  Anything higher than low heat will scorch the fat; anything short of
VERY long will leave it incompletely rendered.  I heat the fat for several
hours, strain out the smallest chunks of rind; then heat overnight.
Once you've got a pan of completely rendered fat, it should cool into a
solid, candle-like white substance.  Heat again on very low heat to make
liquid.  I half-fill a muffin pan with powdered jerky and spoon in the
liquid fat until it "looks right."  The top of the "muffin" should be
wet-looking, but not runny.  When the fat cools to a solid white again, it
will hold the meat together.

Hope this helps.

Robert