Now I'm really worried about my query letter writing ability.
Don't stress about that blog, Shadow. This Anonymous Author has some very good advice on writing a query, but it also has some advice with which I disagree.
The first bit that caught my attention as wholly untrue was in the blogger's first paragraph:
No big publishing houses will even think about looking at your stuff unless it's submitted by a real, live literary agent.
Not true, not true at all. Some big houses still accept unagented manuscripts. Do agents increase your chance of being read at a big house? Heck, yes. Are you screwed six ways from Sundway without an agent? No.
From part 3:
I don't know how many times I've been warned about saying it's my first novel. The agent doesn't need to know that. If you've been published, say so. If you haven't, leave it out completely.
Also, don't play mind games with the agent. Puffing yourself up could, in the long run, make you look like a fool if the agent ever calls you on your BS. Lying about quotes is dishonest and is a bad foundation for building a working relationship with a prospective agent.

The blogger can call it "stretching" if he/she likes, but it's still lying.