But most importantly, do your homework BEFORE you submit. Most publishing houses have their submission guidelines on their websites.
In reality, this is your first test as an author. Can you follow simple guidelines? Can you do what is asked of you in the general form?
You may be quirking your brow and thinking, What? A test? Seriously?
Yes. Maybe not a serious, sit down, use a #2 pencil type one, and maybe not in the terms any publishing house would actually use, but there are editors on the other end of that submission email. Trust me, those editors quirk their brows at someone who sent multiple attachments when it was specifically asked that no attachments be sent with a query, or when you use a really weird and fancy font when a simple Times New Roman 12 was specified. No, you aren't physically graded, but not adhering to simple guidelines can start you off on the wrong foot with someone that you really want to impress. They need to know you can follow simple directions so that when it's time for the more in-depth directions of edits on your manuscript, they know up front you are someone they can work with.
So, show them you are someone they want to work with. Show them you are someone they CAN work with. Show them you are serious and took the time to research their site. This effort shows them you are someone willing to learn and willing to work for your craft.
And I'll let you in on a secret, those are the answers to that first test called Submission Etiquette 101.
Do your homework and you'll ace it every time!