What is the easiest way to insert a clip on the timeline in a completed project? The type of project that I am referring to is a wedding highlights piece where I want to insert an additional clip between two others on the timeline. I currently select everything to the right of the insertion point for the additional clip and group them together. They can then be moved to the right as a group to allow room for the new clip without affecting the clips and their transitions etc. that are already on the timeline. It seems to me there is probably an easier way to do this that I am missing.

Works for me. I haven't found a better or faster way to do it either.

What I do sometimes (when I remember) is move the first clip to the right of where I want the hole for the new clip then hit the F key and that will move all the rest of the clips to the right of the first clip I moved and keep transitions intact.
Either way it comes out the same

Turn on Auto Ripple mode (it is important!) and drag'n'drop the clip between two others (drop it when you see the highlighted snap indicator). Voila!

Thank you! That will save a lot of time.