he major wines of Venice are Soave (white) and Valpolicella (red). Bardolino is also a good choice as an alternative red and, of course, Mr Pinot is always on very good terms with Mr Grigio. The sparkling wine of Venice is Proscecco. 
No visit to Venice would be complete without the "real" cocktail of Venice, the Spritz . It comprises white wine - often sparkling prosecco or, if not, wine plus sparkling water - and Campari. Variations include substituting the Campari with Aperol (sweeter), or, occasionally, Select or Cynar. Looks and tastes great. This is the orange coloured drink you see all Venetians drinking in the early evening and is definitely one for relaxing and people watching. 
Make your own Spritz: 

To a small/medium tumbler add:* 
2 part Campari or Aperol 
2 part white wine 
1 part soda water 
Alternatively, substitute the white wine and soda water with Prosecco in equal measure to the Campari or Aperol (definitely a better, but more expensive mix) 
Garnish with one 1/2 slice of orange and an unpitted olive on a cocktail stick 
* Adjust proportions to suit your taste 
Listed below are a couple of notable places to drink in whilst in Venice. These are top end and expensive but probably worth doing once (or more if you're flush) 
Harry's Bar 
I guess you have to have a Bellini whilst in Venice. It is a mix of Prosecco and white peach pulp. So where better to have one than in the place it was invented?. Very expensive (€15+?) so do it once and tick the box. HINT: Do not be tempted to buy one of the bottles of lurid pink "Bellini" that you see in all the tourist shops. They are not real Bellinis and taste ghastly. 
Skyline Bar, Hilton Stucky Hotel, Giudecca 
Let's not beat about the bush - you are going to pay a fortune here. But if the idea of taking a cocktail at dusk overlooking the Giudecca canal and across the rooftops of the Serene City as the stars come out and the lights of the City start to glow, well...... 
This is a fabulously cool bar in a new hotel built into a renovated factory. Getting there is a bit of an exercise but goes something like this. Take the vaporreto to San Eufemia across the canal, disembark and turn right. The hotel is a huge, square building about 400 metres from the stop. The bar is on the 8th floor. 
When I last went in March 2019 it was not very busy. That might be a different story in high season. Oh, and the bar doesn't open until around 6pm. 
There are watering holes all over Venice and a quick departure from the main thoroughfares will bring you a good atmosphere and better prices. It is not uncommon to see people standing in the street enjoying a wine or beer bought from a bar that faces onto it. The bacari (bars) of Venice are famous for their atmosphere - they are a MUST to visit. Go here for some suggestions