In planning a full funnel B2B content marketing strategy the best place to start is with your customer journey. Mapping out what it is today, overlaying analytics on that, and then also reviewing what you think it should be. Are there areas you need to add, areas which need improvement or more budget.
This naturally helps you plan out what activity needs to be done and where. Analytics plays a vital role, in helping to measure progress as you execute on your plan.
A pro tip is to also think about post-purchase. What can be done post purchase, to help with retention, revenue expansion and referrals. Content can play a vital role there too.