Why does my venison jerky always come out either bone dry or rubbery?

I got a nice deer this season and wanted to make use of the trim for jerky in my home dehydrator. I cut it with the grain, like I was told, but I can't seem to get the texture right. It's either like eating leather or it's weirdly soft and chewy. Any tips on marinating time or temperature to hit that perfect pull-apart consistency?