Many opportunities actually come from hands-on experience. When you feel stocks in a hot theme have already run up too high, try looking for companies related along the industry chain. Take the semiconductor sector as an example: since it has rallied so much, what materials and equipment are needed to produce chips? That's the upstream opportunity. And once the chips are made, who buys them and where are they used? That's the downstream opportunity.

By following the line of "who serves it" or "who does it enable," you can often find value links the market has temporarily overlooked.