Law 23 of Robert Greene's The 48 Laws of Power is "Concentrate Your Forces". It states that you should focus your energy and resources on a single goal, rather than spreading them out. 

Why it's importantYou can achieve more by focusing on one thing deeply than by trying many things halfheartedly. 

You can increase your chances of success by channeling your energy strategically. 

You can avoid the risk of being tied to a single source of power by diversifying your sources. 

Examples of successful application 

Alexander the GreatFocused his forces on key points of resistance, which led to rapid victories.Steve JobsFocused Apple's resources on a few key products, which led to the development of the iPhone and iPad.How to applyIdentify a specific goal and focus all your energy on achieving it. 

Find a mentor with expertise in your chosen field and build a strong relationship with them. 

Focus your efforts on your most important goals.