Well, I suppose it depends on the pub, but most of the pubs I go to have a pretty decent choice of wines by the glass. There's usually a list either on a board behind the bar, or on a menu on the bar and tables.
Common red wines served in pubs are Cabernet Sauvignon, Shiraz, Merlot. If you'd prefer white, the most common served in pubs are Sauvignon Blanc, Pinot Grigio & Chardonnay. There's often a choice of country of origin e.g. Chilean Sauvignon Blanc (cheapest) or New Zealand. You'll be asked if you want a small or large glass, sometimes medium. The large glasses are massive, often 250ml which is a third of a bottle.
Lots of pubs do Prosecco by the glass aswell.
Beers and lagers will be on draft but there will be lots of bottled too. Peroni is fashionable and more expensive (and delicious). Order large or small - approx equal to pint and half pint. Budweiser's popular and widely stocked. For the draft beers and lagers, pick a name of the pumps or just ask for half a lager, for example, and they'll give you one of their house brews.
Most young women I know start the evening with wine or bottled lager/beer but may move on to shots later. Gin and vodka are currently fashionable.
Finally, some pubs have cocktail menus. These are expensive and have a lot of alcohol in so I wouldn't recommend if you are not a practised drinker. They are delicious though!