A real long-term business strategy is simply a reflection of your personal goals. You first have to decide what kind of company you want to run. On Honest Ecommerce, Marc Bacher of Stuga put it perfectly when he asked if you want to just make a bunch of money, or if you want to build a business and a lifestyle for yourself. For him, the focus is on living a great life and making an impact, which is why he invests in building a solid, long-term foundation. That choice between a quick flip, a lifestyle brand, or a legacy project is the true starting point.
Once you know your destination, you can build a sustainable engine to get there. The most effective way to build a lasting business is by creating a diversified source of content and marketing. Jimmy MacDonald of Authenticity50 explained on Honest Ecommerce that this "flywheel" approach, where channels create synergies and lift each other up, is more effective over time. It takes longer than chasing short-term hacks, but as Freeman Cui mentioned on the Serious Sellers Podcast, it's essential if you want to build a brand that can exist for decades.
Your first step isn't to write a 20-page plan. It's to decide what you actually want from the business personally.