There are no trade secrets to visiting a winery, just the broad rules that tend to govern all good things in life: ask questions, be up for anything, and always tread with respect.
At a bottle shop
What's a great wine region nearby to visit?
If you want some advice on wine travel, ask the people who sell wine for a living. They've often visited many of the local regions and can point to a favourite. To get the best results, ask for a region, and then one or two wineries, restaurants or attractions to get you started. If I were asked, a few of my top picks would be: Yarra Valley, kicking off at Graceburn Wine Room, Four Pillars Gin distillery and Yarra Yering; Beechworth, making sure to check out Provenance restaurant and Pennyweight winery; and Orange, stopping at Philip Shaw's cellar door and Union Bank and Racine restaurants.
At a wine region restaurant
Where else in town do you recommend going?
The secret to wine travel is not to plan too much. When researching a trip, it can be hard to tell what looks good on paper and what delivers in real life. The locals will know. When you've made contact at a winery or restaurant, ask the people working there if they have suggestions of places to go and things to do. You'll often find spots that might be a bit under the radar, or don't usually accept visitors. Some experiences I've discovered with this philosophy include combing the basement cellar for aged bottles at the Victory Hotel in McLaren Vale; having after-dinner negronis at The Press Room wine bar in Beechworth; and strolling the Cataract Gorge Reserve after lunch at Stillwater in Launceston.
At a winery
Can we have a quick look around?
Once you have some wine region and winery suggestions, figuring out the rules of engagement is next. A search on the winery's website can usually tell you their opening hours and cellar door policy. If they don't list any opening hours or cite "by appointment only" terms, don't be discouraged. Most wineries are happy to have visitors, and if they're not, there's no harm in asking. And they may have other suggestions if they're not able to host you. A succinct email or phone call usually does the trick. Politeness and respect are all when requesting a visit. Most producers are more than happy to entertain guests who are considerate and engaged.