<p data-pm-slice="1 1 []">Before planning your birthday decoration, consider who the celebration is for, whether the party will be held indoors or outdoors, and which colours or themes you prefer. A child's birthday may suit cartoon themes and colourful balloons, while an adult's celebration may look better with elegant construction backdrops and personalised decor. These details help you create a setup that matches the occasion, space, and personal style.