To understand the competitive dynamics in a market, I can be fruitful to ask yourself, or better yet, people operating in that particular market the silver bullet question:
If you had one silver bullet, which competitor would you take out?
The mental exercise was popularized by Warren Buffett which he adopted from Andy Grove of Intel. He used the Silver Bullet Test when thinking about Strategic Inflection Points. If you have been asking yourself this question routinely and all of a sudden, you find yourself changing the direction of the gun towards a new target, it might indicate that the competitive forces in the marketplace are shifting.