Each customer acquisition channel has its own constraints. Knowing how long it will take to get results, the costs, the amount of customers, if you're in control and how detailed the targeting is can be a great factor in deciding what channel to pursue. If you match the constraints of each channel, with the needs of your business, it suddenly got a lot easier to decide which channel could work.
Let me be honest with you. What I’m going to tell you, it's not rocket science. However, if you use it as a first-order principle, a factor to base your decision on and always hold in mind when talking about customer acquisition channels and content, it will do you great.