I usually get a good mileage out of jumping straight in the middle :). Like, "hmm let's look at this block; oh cool, there's enough space around it that I could push it away from goal, for whatever reason". Turns out, if it's possible there usually is a good reason. So whenever I get stuck, I skim every object in the puzzle and consider in isolation, what can I do with it, and this usually gives me anchor points to drive my forward or backward thinking through.