Replying to Colorado Residency

I'm a senior in high school and I'm still not sure where I'm going to college. I've been considering somewhere out west and Colorado. My main problem is gaining residency to qualify for in state tuition. I understand that I must work and be able to support myself and other things.

My main questions are
what exactly is the easiest way to gain residency?

Is it possible to find a job and support myself for a whole year?

I do not qualify for domicile as I will be 18 and have no relatives there