The dreaded synopsis.. What's your method?

I'm about to send out wave #2 of query letters, this time with a single page synopsis included.

Most articles I read say to include the ending for a number of reasons.. It's so difficult to condense a feature-length screenplay into a single page, and make it as compelling as it needs to be to get a positive reply.

I've started my synopsis four times now. It's either too detailed, or too vague.

What's your method?