RE: Leaving my pets for vacation for the first time.
Oh, it's painful having to leave pets isn't it?
I'm in the fortunate position right now that my in-laws actually live quite close to us, so if we have to go away for any reason, whether that's for vacations or work-related stuff we are able to drop our dog and cat off with them. My in-laws also have a Shih Tzu, so our pets also have an extra play mate when we go away.
My mother in law also lavishes them with treats, and quite honestly I think they feel as if they are on a vacation too! They're probably disappointed when they have to come back home again!
I think that's probably my best tip - maybe get a couple of new toys, and some special yummy treats for your pets so that they feel like you being away is almost something to look forward to because of all the fun stuff they get to play with and eat!