Creating floral designs that catch a viewers eyes is a skill which good flower designers have. Just like an artist who creates a piece of artwork that captures the viewers attention, the florist needs to be able to create a design that pulls a viewer into a floral design. When pullled into the design, the viewer experiences something that must be good about the designer. It will help them to think positively about the designer.
You have all the time to rearrange or polish your flower arrangement. The flower design should look beautiful and artistic enough before you place your filler, when the filler is already placed, it would be harder to move your things around the area or place. Bear in mind that The filler are very fragile.