When using a cocktail shaker there is one golden rule to remember. Always put the ice in the shaker first, and the liquor last. This is to ensure that all ingredients are properly chilled by the ice when they are poured over the ice, and by adding the liquor last you reduce the chance of dilution.
The purpose of floating is to keep each ingredients in the drink in separate layers that do not mix with the others. This will create a drink with separate layers, and this is why floating often is referred to as layering.
The easiest way to float one liquor on top of another is to use a demitasse spoon, holding it over or in the glass and slowly trickle the ingredient over the back of the spoon.
Instead of stirring, you can shake the drink. This will mix the ingredients more than stirring, but will also result in a less clear drink. Drinks that contain ingredients that are hard to mix, such as cream, fruit juices and eggs, should be shaken vigorously to ensure that the ingredients has been well mixed.
Use an electric blender to mix fresh fruit, liquor, juices and ice instead of using a shaker. Not too popular everywhere, but perfect for making frozen cocktails or to blend ingredients that are otherwise impossible to mix.
A drink that is stirred instead of shaken will retain its clarity and be free of ice chips. Drinks based on clear liquors, like a Martini, should always be stirred and not shaken (don't listen to James Bond when he order his Martini "shaken, not stirred").
When stirring a cocktail you should stir it enough to mix the ingredients, but not stir it too much. If you stir too much the ice will begin to dilute the liquor. A general rule is that 10-15 stirs will be sufficient for proper mixing.
A drink containing carbonated beverage(s) should be stirred gently and briefly to retain the sparkle.
Muddling is a simple mashing technique for grinding herbs, such as mint, smooth in the bottom of a glass. You can use a wooden muddler that you buy in a bar supply store or buy a bar spoon with a muddler on the end. It crushes the herbs, much as the back of a soup spoon might, without scaring the glass.
To frost a glass, first dip it in water and then put it in the freezer for half an hour or so. Also note that metal and silver mugs and cups will frost better than glasses.