In my opinion, IA is not something that needs to be sold. IA is already inherent to whatever someone is working on or has in place. If you are making something, you will be tackling the IA within and around it. With or without me you will “do IA.”
I guess in sales speak we could say “IA is included for free in all projects” — because a system without an information architecture does not exist. Rather than selling information architecture, I find that I do have to “explain” what it is and why it matters so that it can be worked on and improved upon (not ignored or inherited which is all too often the case)
Whether you're interested in "selling" IA or not, the fact is you'll probably have to explain what you do to others. Probably multiple times. Per day. You could do worse than have a few of Abby's scripts memorized.