“Think in the Round.”
Before you pull out your sketchbook and pencils, take some time to consider your subject from all angles. If you happen to be in the woods and stumble upon an amazing looking tree, don’t start drawing right away. Instead, go for a walk around the tree first. Try varying your perspective by getting low to the ground or finding a higher vantage point. From which side does the light look best? Soak it all in and explore all your options.
Thinking in the round also works for smaller subjects. Just rotate and sketch like I’ve done with this crab claw. You'll get a far better understanding of your subject by working it from all sides.
This tip also applies to photography. The next time you’re on vacation and standing before a famous landmark, try to think in the round. You'll come away with images more memorable than the usual tourist snapshots.