In writing, transitions are subtle. The knitting together of character, thoughts, and action into a narrative should be almost invisible. But in a speech, transitions that bridge the gaps from one topic to another are much more obvious because you have to be sure your listeners cross the bridge with you. If the transition is too subtle, they may miss it and remain on topic A, while you are well launched into topic B. An effective transition always lets the audience know you are moving from one point to another. The process can be straightforward or creative, depending on the device you use.