The priorities are 1) Audience, 2) Offer, and 3) Creative. In that order.
When building a direct mail fundraising campaign it is often tempting to focus the most time and effort on the creative. After all, most people gravitate to the visual components because they’re the easiest to understand and critique.
In reality though, getting the audience (who you mail) right is the most critical part of the planning process. After that the offer (why someone should give, and why now) is next in importance. In fact, these two components account for 80% – 90% of the success of your mailings.
Creative is relevant and important, but is significantly less important in the grand scheme than are the audience and offer.