Use wider aperture to narrow the depth of field and to make elements in the foreground and background more and more out of focus. If the flower plant is in a pot move it to a new location for the shot so as to have plain dark background.
Sometimes going in extra close and focusing on a part of the flower can create wonderful and unusual images that take on an abstract quality. So, look for contrasting colors, patterns and textures for this purpose.
Sharp focus is important in flower Macro photography which can be a real challenge on a breezy day. Try to avoid the use of a flash as it is likely to wash the photograph. If the light is too less, use a diffuser over the flash for a more natural looking shot.
The inset photograph shows a macro-set tight photograph a flower with a bee sitting on it. The distracting elements of other plants in the garden have been cropped for a tighter shot.