Be sure to keep the following ingredients on hand at all times to be able to make some wonderful drinks for yourself and friends at home.
You will definitely want to have lemons and limes for juicing. Oranges and grapefruits would be a great addition, for an unsweetened and fresh alternative. Depending on the drink, any citrus can make for a great garnish.
Equal parts water and granulated sugar, you can heat it up if you would like or combine in a bottle and shake really hard if you don't want to wait. There are a lot of flavor possibilities here if you want to experiment with ingredients like ginger, mint, cinnamon, raspberries, or rosemary.
Have some small bottles, or cans, on hand at all times for the "vodka soda" crowd, and a little splash can liven up a lot of different drinks. Called for in classics like a gin fizz and a vodka collins.
Gin and tonic anyone? Just remember, this stuff is bitter and sweet. In case you were wondering, it originally was used, in India, by the British to fight off malaria with the quinine in it. They would also add gin, lime, and sugar to the tonic water to make it drinkable. Nowadays there is a lot less quinine but we still enjoy it.
A lot of people don't seem to understand vermouth. It is simply a fortified wine (alcohol is added) that has botanicals added. It comes in two main forms, both of which you should have stocked in your refrigerator, Dry Vermouth and Sweet Vermouth. Dry vermouth is vitally important to making a real martini and sweet vermouth is essential to the Negroni and The Manhattan. Once opened, they should be stored in the fridge.
You will most likely want to start with a bottle of Angostura aromatic bitters if nothing else. Orange bitters would be the next to pick up a bottle of. Then you can go crazy and try all kinds of different bitters that are available these days to add interesting flavors and variations to really simple drinks like a gin and tonic or a martini
This is a matter of preference. There are all kinds of flavored and sweetened liqueurs out there to try, look into some drinks that use a liqueur and your favorite spirits. A couple to consider would be a bitter liqueur (amaro) like Campari, orange liqueur, coffee liqueur, or even amaretto.
If you want to be able to mix up some drinks at home, you will want to be sure to have yourself the above ingredients on hand. Once you get an idea of what types of drinks you like, you can focus on just having those ingredients. It wouldn't hurt to have all of the above if you want to share with friends.
Be sure to share this with anyone who might need the advice.