There are four basic methods that can be used to edit clips in iMovie. Once you have mastered these you will be able to discover a myriad of ways that you can combine them to get the result that you want. Each method can be undone by selecting Edit>Undo or pressing Z.
Selecting part of a clip
To put the following editing methods to use you must first learn to select a part of a clip. To do so begin by placing the playhead at a particular point in the scrubber bar. Then, while holding the shift key, click a second point on the scrubber bar. You can adjust these points by clicking and dragging the small triangles, (in and out markers).
Method One: Deleting
Select the part of the clip that you wish to delete and then press the <Delete> key. If you delete from the middle of a clip you will create two clips - one for each end.
Method Two: Cropping
Select the part of the clip that you wish to keep and then select Edit>Crop or press <Cmd>. The ends will disappear and you will be left with the part you wished to keep.
Method Three: Duplicating
Select a clip or a part of a clip that you wish to duplicate. Copy it by selecting Edit>Copy or pressing C. Then paste it by selecting Edit>Paste or pressing <Cmd>V. A duplicate will be created. You may edit each clip individually, as they are not connected in any way.
Method Four: Splitting
Move the playhead to the point at which you wish to split the clip. Spit the clip into two parts by choosing Edit>Split Clip at Playhead or by pressing <Cmd>T.
The clip will be split into two parts. If the clips are adjacent to each other they will play like a single clip without loss of either picture quality or sound continuity.
When you have completed editing and ordering the clips, you will be ready to add the titles, transitions and sounds that will bring your movie to life.