Most of the ways to drink brandy depend on the age of the brandy. Most older brandies should be sipped over ice or drunk just neat without ice or any mixers. Older brandies have more diverse and enjoyable flavors.
Drinks in which brandy is combined with mixers are typically intended for after-dinner or social drinking situations. If the brandy is a cheap brand, it should be combined with other liquors or mixers to improve the taste. As with most alcohols, cheaper brandy tends to have a more unpleasant taste; a cheap brandy is more likely to ruin the drinker's experience.