Create a smooth edge along the first side of the transition. For example, when laying the short end of wood planks, they must all match each other along the edge, without one being either shorter or longer than the others. No matter the material, this is important for an attractive transition. There is no covering material to hide any gaps in the transition.
Lay your transition material butt against the edge of the floor material that you just put down. For example, if you're laying maple-colored laminate planks in the kitchen and you want cherry planks in the dining room which is joined by a doorway, then you might use a 4-inch square tile as the transition material. One 36-inch row of tile in the doorway between the two rooms requires a minimal amount of work.
Lay the tile with the proper adhesive and ensure that the free side is perfectly straight after the tiling is finished.
Place the second floor material butt against the other side of the transition point without leaving a gap between the material and continue the floor installation. When you rub your hand over the transition point, you should hardly notice a change in the height of the three materials.