Newbie asks about Brent/WTI correlation with other factors

I've been trading oil for a while now, but I still feel like I can't quite get a grasp on the direction. Whenever WTI or Brent moves sharply up/down, I often see news about the dollar index or GDP growth coming out at the same time. I'd like to know how other traders look at these correlations, or what indicators they use to help assess their relationships. Right now, I'm trying to look at historical charts, but I'm still confused about which factors have more weight.