1. Go on the weekend
We kinda flubbed this by planning our tour day on a Tuesday. We signed up for a tour, which was great, however our group consisted of middle-aged couples. If you do your touring on the weekends you have a much better chance of spending the day with likeminded girls or if your lucky, even a group of guys.
If you have a big enough group, you can also just rent your own bus for around $20 a person and explore/drink at your leisure.
2. Stay at the Best Western Elm House
I could't have envisioned a better place to stay in Napa. Not only was it reasonably priced ($240 a night) but the breakfast buffet in the morning is something to write home about (or text pictures too). We're talking sweet potato waffles and freshly baked muffins and oatmeal with every topping imaginable. And if you are a coffee addict like I am, they have a beautiful little garden terrace outside with heated lamps that you can quietly enjoy your morning coffee in. The one small complain about this was that our air conditioning unit was extremely loud and woke us up at night a lot, so request a room with a quieter one, if that exists...
Tip: You can also walk to downtown Napa from here. It's about a mile walk which isn't bad considering that cabs are pretty much nonexistent.
3. Leave room in your luggage for wine
When packing your suitcase for your trip, remember to leave some extra poundage in your luggage. You will want to buy wine at the wineries and not have to pay a $40 plus shipping fee to have it to sent home to you. Most wineries sell a bubble wrap case for around $3 that you can safely insert your purchase to. Each wine bottle weighs roughly 6 pounds. And with that 50lb weight limit for flights, you may only be able to pack 1 cute maxi dress to fit all of your other ehhemm purchases....
Tip: Some wineries will give you a discount if you post a photo on Facebook and tag them in it. I took advantage of this at Hagafen Cellars. This winery also has some great backgrounds for photos (see below).