Begin with the recipient’s own taste
Consider the colours they choose in everyday life and the floral style that feels familiar to them. A clean bouquet, a loose garden arrangement or a strong designer accent can all work; personal preference is more useful than generic rules based on age or profession.
When their favourites are unknown, use the setting as your guide. An arrangement that is easy to place in water suits a workplace, a more generous format can work at home, and a bouquet for a restaurant should be comfortable to hold and carry.