Mixer

Mixers are non-alcoholic ingredients in cocktails. Mixers include things like grenadine, soda, non-liqueur syrups, and juices.

Carbonated mixers and sodas
Carbonated mixers are based on carbonated water. Due to certain properties of gas-liquid solutions and gas solubility, carbonated water does not stay carbonated for long; it quickly goes flat. Because heat decreases solubility of gases, and because an open container allows the pressure on top the solution to stay below the vapor pressure of carbon dioxide, you should always make sure carbonated mixers are kept in a keg or cold, closed bottle.
For soda fountains and soda guns, carbonated water is mixed for soda, colas, and tonic water by passing water through syrup and introducing carbon dioxide gas into the line from a pressurized tank. This ensures that the carbonation is always fresh, not weak or flat. Kegs usually come with a pump to allow them to be pressurized; you can purchase small pumps to replace soda bottle caps for the same reason, but they're rarely worth the effort except for very rarely used bottles. Remember, gases evaporate from water under low pressure; high pressure fixes this.
For carbonated mixers in bottles, try keeping smaller bottles for mixers that are used slowly throughout the night; use bigger bottles only for really popular mixers that run out fast. In either case, try to keep the cap on when not in use.

• Club Soda
• Coke
• Tonic water
• White Soda

Juices
Whenever possible, use fresh squeezed citrus juices. These juices degrade quickly after being squeezed, and cocktails will not have the expected flavour or balance with sweet and sour mix or commercial bottled juices. For less easily made juices such as pomegranate or pineapple, the drink recipe is likely balanced for bottled juice, so feel free to use those, as long as they are 100% juice without added sweeteners or artificial flavourings.

Cranberry juice

Grapefruit juice

Lemon juice

Lime juice

Lime juice is one of the most common juices found in classic cocktails, as its tart flavour is very effective at balancing sweet liqueurs like TripleSec, and its character has a natural synergy with the aromatic botanicals of dry gin. If used in a cocktail without a sweeter liqueur or juice, it is often sweetened with a small amount of simple syrup so as not to be unpleasantly tart. Lime juice is also a bit inconsistent compared to other citrus juices, so one must be sure to taste a cocktail and balance for it before serving.

Rose's lime juice

Rose's is a lime juice cordial, with sugar and preservatives added. It is a very specific flavour, which is often specified in Gimlet recipes. However, given the current availability of fresh limes in most parts of the developed world, it should never be substituted in recipes calling for "lime juice", only those calling for lime juice cordial or Rose's specifically.

Orange juice

Pineapple juice

Syrups

• Grenadine
• Peach nectar
• Simple syrup

Bitters

• Angostura bitters
• Orange bitters
• Campari

Other

• Cream
• Ice
• Milk
• Water
• Egg White

Source: wikibooks.org - the open-content textbooks collection