Its based on biome selection. @bucfanpaka has posted quite a bit on the subject…
I was trying to find the thread where she explains the different set ups for gems and such for you, but she has posted a lot on the subject
But you can somewhat control resources through proper biome selection. Getting duds still happens though, so your best bet is to start out month to month.
Don’t apply fuel until you’ve rolled one you like (and if @Turrican2006 is still doing it, you can ask him to test your new sovereign to see just how rich it really is as concentration can be better than high %)
Pakaworlds
World builds thread
Here’s some good info