If you are like me you don't call yourself an editor, but you find yourself cutting a lot of your own projects. I direct more than anything, but not every project has the budget for an editor so I end up doing it myself. I prefer having someone else edit. Mainly for time, but it is helpful to get fresh eyes on something you directed or DP'ed. The positive to knowing how to edit is it helps develop your story telling skills.
The first thing I do when I start editing is I organize files. This is obvious to most people, but it takes time and patience to organize all those clips. It's tempting to just start grabbing clips and throwing them on a timeline and start cutting. I look at organizing files like preproduction for a shoot. The more organized you are in pre the easier the actual production days are. So if you take the time to get organized before editing the more efficient you can be when you actually start.
For this most recent short film I directed, I organized all of my clips into bins specified by scenes. If this would have been a longer project I would actually label every clip by its scene, shot number, and take. This is the industry standard, but I didn't find it necessary for a film with only 12 scenes.
WATCH ALL THE FOOTAGE
I used to just scrub through clips, but I've learned that actually watching all of your footage is helpful. Even if you were on set the day of the shoot operating camera and directing there will be things you don't remember happening in any given take. You may actually be surprised by what you find. Like organizing clips, this takes more time, but it's well worth it when you find that one golden take that wasn't expected.
Martin Scorsese said, "If you don't get physically ill after seeing your first rough cut somethings wrong." The more experience I've had with filmmaking the more and more this statement has become true. Often I panic after I finalize a rough cut. My first thought is, "This isn't going to work." There's a reason it's called a rough cut. I honestly don't show anyone my first edit for this reason. I use this panic to drive me to edit more. Editing is all about refining the story. So just keep editing.
WIDE, MEDIUM, TIGHT, REPEAT
In any given story it helps the audience to start a scene with a wide establishing shot. It helps them understand the environment the actors are living in. Wide shots also orient the audience in a way they can understand how the actors relate to their environment. Then you can move into medium and close up shots. This is a time honored rule that editors live by for good reason. However, I break the rule at times. Maybe I want to disorient the audience at the beginning of a scene. I may start on a close up and then cut to a wide to reveal what the character is reacting to. This leads to my next point. Trust your gut.
TRUST YOUR GUT
Editing is a weird blend of art and technical skill like most parts of filmmaking. There are rules to follow and to be broken. For me it really comes down to trusting your gut. You don't have to rationalize every decision you make. Most of the time you have to just trust what you feel and cut according to that. It's sort of like Obi Wan Kenobi telling Luke, "Use the force. Trust your feelings."
After my third revision of the entire edit, I'm usually at a place where I can show someone else and get some outside opinions. I have three people I'll show a non finalized edit to. Two of them are directors I respect, and the third is my wife. I want to hear from people I respect and don't want to muddy the waters with too many outside opinions. I certainly won't show a client any version other than the final edit.
I'm surprised by how showing someone else a cut effects me. Especially if I watch the edit with them in person. It's like I'm seeing the story through their eyes. Before they even say anything, I know what they are going to say. Having an outside view will help you see the holes in the edit. It will help you see where the story is unclear. This will save you tons of time just trying to fix things on your own.
Every film can be edited an infinite number of times. That's why we have director's cuts. But there are deadlines and you do have to eventually deliver a final edit. Don't prolong the process longer than it needs to be. Sure, if you are waiting on pick up shots an extended deadline is acceptable. But you, as the editor, have to deliver the film.