Provide a convincing cover story. You know that story about a fixed supply of 21 million coins? That fearful creator who disappeared? The highly convoluted decentralised and trust-free structure, the Bitcoin Rube Goldberg machine, because centralisation is evil? It's a stroke of genius from a marketing point of view (assuming it wasn't all a hilarious cosmic accident).
Whatever alternative you promote, like:
--demurrage or perpetual inflation
--some element of centrally planned spending that covers more than just network maintenance.
--smarter inflation that dis-empowers speculators,
or some balanced combination, you'll probably find that at best you'll get a lukewarm reception (think: polite clapping) from a small number of pragmatic, reasonable people who stumble upon your idea. But you won't gain traction unless you rally some religious fervour to give your cause a kick-start and also give it protective padding against growth pains. You really need to figure this out.