There's a lot of talk about being #1 on Google. It's important, because most searchers home in on the first site in a list of search results, and very few searchers go beyond the first page of results.
The problem is this: you can be #1 on Google for a search phrase that no one uses. That's useless (which is why you should be skeptical of people offering to "make you #1 on Google").
You should be #1 on Google for the name of your winery (and the commonly used alternatives). For example, if your winery is named Acme Winery, you should aim to be #1 for Acme wines as well as Acme Winery.
Of course, that only covers people who are searching for your winery by name, which is just a fraction of the searches that could be leading people to your winery. You also want to be highly ranked for the searches that potential customers are making (more about this soon).
Incidentally, you should type the name of your winery into the Google Adwords Keyword Tool. It will show you the various ways in which people search for your winery, and which are the most frequently used.