Let's see how many will disagree with me
When I started playing with rubs, I gathered the flavors I liked best-i.e., garlic,onion,NM chile,oregano,cumin,etc. and mixed them in different mixes to find the one I liked. Then I tweeked it to what I use now. You can go with a sweet rub, savory,dry(nothing on the meat except the rub) ,wet(with most anything) or just use your imagination.
However some go to a supermarket and get a pre-made commercial rub like Emeril's or from one of the site on the net. Plenty of sources out there. I just happen to like mine. That's just me though
Play a bit, you may come up with a really great rub. Here's an idea...
ground Juniper Berries
It'll give you a real campout taste, and it's rather good too
Have fun and