One question to start with is – is the goal to target existing customers or attract new ones (or both)? Then figure out where that audience is and how you can most effectively reach them.
Another is resourcing and scope - what can you pull off in the timeframe you have, and prioritize from there.
Another would be, do you want to experiment with new channels (and do you have the resources/risk appetite/budget)? For example, we have an upcoming launch and we're looking into new social channels: Instagram and TikTok. But we've made it a P1-2 priority. We're focused on the channels we know are effective for us and will make a game-time decision on TikTok if we have the bandwidth.