From my experience with sales and copy, the most important aspects to consider are the motivations of the target prospects, and their ability to belive in your ability to help them realize what they want or want to remove. Without their motivation nothing else matters much, honestly.
1. Who are the target customers?
What do you know about them? What's their stage of awareness? What's their level of motivation?
2. What's the offer?
How irresistible is it? Why? What makes it's so?
3. How are you communicating with them?
What medium are you using? Sales letter? Video sales letter? Phone? In person? All of that has a bearing on how persuasive and influential your message is.
4. What's the COST?
Cost is different from price in it's the total overall allotment of resources involved including the amount of time it might take, how much motivation there is to get the thing accomplished (is it a want or a need?), and how much of abearing on status this accomplishment might have. The last (but not last in sequence) concern is the amount of money exchange involved.
What assets can we leverage to make this a no brainer for either party? What underutilized or unrealized assets can we make use of that might make this an easy thing to achieve?
6. Any past successes?
Who else has achieved what we're going for here? How sure are we that this is even achievable to begin wtih?
Do we have any proof to refer to?
7. Why are you qualified to help achievement?
Have you pulled this off before? For yourself? For others? What qualifies you to be able to offer this?