First, secure intelligence, logistics, and support firepower, then consider tactics—that is, the specifics of how to fight. Even though this was only a battle involving dozens of people, Gao Guang still implemented the principle of "plan thoroughly before taking action" very comprehensively.
As a cultured person from Huaxia, military strategies are hardwired into his genes. Things like "The Art of War by Sun Tzu" and the "Thirty-Six Stratagems" are common knowledge—whether you've read them or not, you've likely heard them mentioned. If you haven't heard them mentioned, through books, operas, movies, television, and animations, you would have absorbed some knowledge through cultural osmosis.
He might be lacking a bit in practical experience, but this theoretical knowledge is absolutely indispensable.