While the origins of the garnish are not definite (the English etymology is from the French word ‘garnir’) the practice of accentuating dishes and drinks aesthetically is globally practiced.
The garnish is normally associated with fine dining drinks and meals but often times the actual garnish ingredients are parts of foods or flowers that would be put to waste in the cooking and mixing process.
The purpose of garnishing can be solely for visual pleasure but the garnish can also be edible and compliment the flavors of a dish. Guidelines for selecting your garnishes are more flexible now than ever and experimentation is encouraged.
Floral garnishes are common, and often delicious, including the best bite of food I have ever experienced a squash flower on a sea bass. More traditional garnishes include spices and citrus and are always a safe bet, especially for cocktails.
If you are looking for garnish inspo there are amazing accounts but @onedrinkaday.