Although you know how you got from point A. to point B., your listeners might not know--help them!
Describe "mechanical transition."
Description: the simplest type of transition.
Example: You've indicated that there are three reasons for something and talked about the first reason; then you simply say, "the second reason...".
Describe "relational transition."
Description: a transition that ties two points of a presentation together.
Example: In a presentation on Army wheeled vehicles, you might transition by saying something like, "Unlike the xxxx, an aaaa can easilty travel over rough terrain." Then you would talk about vehicle aaaa.
Describe "summarizing transition."
Description: a transition that gives details about points you've already covered, sometimes called an internal summary.
Example: You describe three advantages of a course of action (COA); then you summarize those advantages before saying something like, "However, even though these are distinct advantages to this COA, some disadvantages merit consideration."