Content strategy and content planning are not the same thing much to popular belief. Strategy is the process you go through to get to the planning step, which then leads you to execution.
Strategy, then planning, then execution. If you intend to be successful with your content creation and your content marketing, you need to be able to separate one from the other and do them in the right order.
When it comes to getting started with creating your content the first factor to consider is who are you actually targeting and why is that customer a target. Each person has different intents, motivations, problems and each person requires different content to move them through the buyers journey. You need to determine which content to create to get that move happening from the very beginning.