As you said, some people don't have a knak for cooking
For instance, for many years now, I no longer can bake a brioche and I still don't know why .... The very I made a few years back were so good. Nowadays, silch !! <img src="/images/graemlins/confused.gif" alt="" />

But making jerky is simple ! <img src="/images/graemlins/smile.gif" alt="" />

When I first tried, I just followed Chris and/or Wildcard explanations.
And got good results the first time. Sure, things can be improved, but it was not only edible, but good. <img src="/images/graemlins/cool.gif" alt="" />

Start with small batches, experiment a little with marinade formula and timing.
You really should get some results, quite easily.
If your jerky is not dry enough, let the next batch in the oven for an extra hour (but do not try to increase temp).
The dryer, the longer it will keep...