Most Apple programs use keyboard shortcuts to make their functions easier to access. iMovie is no different than the rest of these, and these shortcuts can make your video-editing project go even quicker.
To start a new project you can just press Apple and N. To open the Project Properties menu, which lets you change things like effect speed and aspect ration, you can just press Apple and J. If you want to move an entire project into the trash can you can click Apple and Delete. If you are trying to import footage from an attached camera or video source you can hit Apple and I, and if you would like to print the movie you can use Apple and P.
To undo an action you can press Apple and Z, and redo that same action you just use Shift, Apple and Z. If you want to select all the clips in a specific area, such as the Timeline, then you can hit Apple and A. To select no clip you can press Apple, Shift, and A. Cut is Apple and X, Copy is Apple and C, and Paste is Apple and V. To delete something you would obviously click Delete, but to delete and entire clip you can press Option and Delete. To open up a menu for special characters, such as Greek letters and unusual mathematical symbols, you can use Control, Apple, and T.
To play a clip you just have to press the Space Bar, and to play in full screen mode you press Apple and G. To export your movie into various file types, hit Apple and E.
To show available text fonts you can press Apple and T. To make the text bold you highlight it and press Shift, Apple, and B. To make it italic you highlight it and press Shift, Apple, and I. For an underline it is Shift, Apple, and U, and for an outline it is Shift, Apple, and O. To make it appear bigger you press Apple and +, and to make it smaller you hit Apple and -. To copy a text style you highlight it and press Option, Apple, and O, and to paste that style you press Option, Apple, and V.
To minimize a viewable window press Apple and M. To open up your computers music selection for use in your iMovie project press Apple and 1. To open photos press Apple and 2. For Titles press Apple and 3, and for transitions you use Apple and 4.
These are the most common keyboard shortcuts for iMovie, but there are still more out there. Start integrating them into your editing and you will begin to see how much faster the process goes.