Anyone can stitch a few clips together on a timeline and add a bit of background music, and that's fine. But, if you want to add a little more depth to your project, it helps to have a broader understanding of editing techniques and shot conventions. Covering them all would take more space in the magazine than my boss is prepared to let me have, but here are a few essentials to get you started.
The establishing shot is, without a doubt, a director's most valuable tool, and is used to tell the audience where the subsequent scenes are taking place. For example, if you take a wide shot of a building in the city and then cut to a scene in a foyer, an office, or even a toilet, the audience will automatically assume that the room they're now looking at is inside the building they were shown previously. If your indoor shot involves windows, be careful that the view through them corresponds to the establishing shot (including lighting and weather conditions).
J to the L
Put simply, J-cuts and L-cuts refer to a specific arrangement of video and audio clips on a timeline, and are also called split-cuts. A J-cut is used to bring the audio associated with a clip into the scene before the accompanying video appears (see this screen shot). An L-cut describes an audio track that continues after the accompanying video disappears (see this screen shot). These are particularly useful in scenes containing dialogue, and you'll see them in television programs all the time - especially holiday programs and documentaries.
For example, you may have a close shot of a presenter standing on a hill describing his location, which then cuts away to wide shots of the surrounding landscape while he continues to speak in the background. This would be an L-cut, because the video and associated audio track makes an L-shape. If you were to show the wide (establishing) shot first with the audio commentary running underneath before cutting to the close shot, it would be a J-cut, because the audio and associated video clip makes a J-shape. Generally speaking, you need an editing application that supports "unlinked" or "disbanded" audio for this kind of edit, but consumer editors with video overlay tracks can also be used - see "Get over it".
Drawing the line
If there's a golden rule when shooting scenes of dialogue, it's "don't cross the line" or the 180-degree rule, and it's something that becomes increasingly difficult in scenes that involve more than two speakers. Picture a basic scene with two people in it. They're talking to each other. Now draw an imaginary line on the ground that runs through the two of them. This is generally called a "the line of interest", but you'll also see it referred to as "the action line" or "the axis line" in some places.
Applying the 180-degree rule means that you can shoot from any point on one side of the line of interest, but you mustn't cross the line and shoot from the other side - unless you have a really, really good reason.
Sticking to this rule preserves the audience's spatial perception of left and right. If you cross the line, this illusion is immediately broken - what appeared to be on the left and facing right beforehand will now look like it's shifted to the right side of the screen and is facing left. It's confusing, and can ruin an otherwise perfectly shot scene.
GET OVER IT
If your editing software is too basic to let you unlink an audio track from the corresponding video track on the timeline, but features an overlay video track, you can still create L- and J-cuts. For example, to create a J-cut, place a clip in the timeline's main video track as shown here (using Studio Plus 9), then place the required lead-in clip on the overlay track. Make sure the overlay is full-screen, and this will achieve exactly the same end result as a conventional J-cut, with the audio from your main clip leading in underneath a different video clip before the main video becomes visible.
SLIP, SLIDE, RIPPLE AND ROLL
There are four very good reasons for you to consider investing in a piece of high-end video software, namely the slip, slide, ripple and roll edit tools. While not essential to construct a video project, these tools can make a huge difference to how you work with clips on the timeline. Here's what they do.
Slip edit: Imagine that you have a sequence of three clips (A, B and C) on the timeline, with no gaps between them. Using the slip tool on clip B lets you change its In and Out points without affecting clip B's duration, or the position of the adjacent clips A and C. It's like the space between clip A and clip C is a window, through which you can see a certain amount of clip B.
Slide edit: The reverse of a slip edit, the slide tool keeps clip B intact, and lets you drag it forwards and backwards on the timeline. For example, if you were to drag it backwards (to the left), the Out point of clip A and the In point of clip C would be moved to an earlier point, reducing the duration of clip A, increasing the duration of clip C, but maintaining the overall duration of the sequence.
Ripple edit: Typically, if you were to crop clip B by dragging the end (handle) of the clip backwards on the timeline, it would leave a gap where clip B ends and clip C begins. Using the ripple edit tool instead will automatically close up any subsequent clips on the timeline to remove the gap. Be careful with ripple edits - it's easy to lose sync with clips on other tracks later on in the sequence.
Roll edit: The roll edit tool basically lets you grab hold of the point where clips meet and drag it to a new position. So, for instance, you might grab the cut point between clip B and clip C and move it forwards (to the right) on the timeline. This would move the Out point of clip B and the In point of clip C to a later point, without changing the length of the overall sequence.