Hey there! Future archaeologist too, huh? *high five!* I, too, want to focus on Classical Archaeology.
Just the thought of it makes me giddy inside. Now, about your personal statement, I'd be happy to help! (Even though, technically, you're competition as Edinburgh is my first choice, as well....
)
Actually, I don't know how to help as I practically whipped up mine out of errant thoughts that seemed to go well together. My advice would be to not want to try and sit down and get it done in one sitting. It didn't work that way for me. Try one paragraph. Then another. And another. Don't worry about order, yet.
Just write one paragraph about each topic (a list of which can be found right here on TSR) and
then work on making it flow. I would also suggest submitting it to the PS Helpers on this site. They are ace and without them, my PS would suck. Trust me, it has been beat up, torn down, and reposted quite a few times but the end result is worth it. Refining it and keeping it original is the hardest part, which is why the phenomenal helpers are there. I've had to write multiple drafts and each one is better than the last.
Anyway, hope this helped!