Camera tricks are often difficult and risky, so there are ways to replicate some of the more standard ones in your editing software.
Many new digital video filmmakers are tempted to do complicated video techniques when they are out filming. This is somewhat forgivable when working on a narrative project where you can try the technique multiple times without fault, or have a number of alternative takes. In “real world" direct cinema moments or interview spots for documentary this can be even more difficult because you presumably have only one chance to get the video. If your camera effect has bad timing or damages an otherwise precise video moment then you are going to lose critical footage. At times it may work much better to do some of these effects in the editing software as opposed to actually during live production.
The slow zoom is one of the most difficult things to actually get right when filming. Even if you are controlling the scene, doing the zoom consistently and on queue is next to impossible no matter what is going on. It can start and stop, change speeds, or come in late. Instead of doing this you can use the principles of photo motion to do this in the editing room. Just take the video clip and set the in and out points in the motion tab where you would like to put the zoom in. Then put the change in size that you want on the end point, and even adjust the image somewhat. This will make it appear to zoom in to the live video. It is best if you do it only a slight bit over an extended period of time, unless you are trying to achieve a novelty effect with a fast zoom. It is also important that it was filmed with a relatively high resolution camera otherwise you may end up out of focus at the end.
The rack focus, which actually films the focusing of an image for effect, suffers from most of the same issues that the zoom has. It is difficult to make it smooth and even the smallest problem with timing can be disastrous. This is much easier to do in the editing software because you do not have to worry about degenerating the image. Set the in and out points for the rack focus and then apply a defocus effect. Then set the effect to start out at the first point and then recede until it is at zero. This will then look as though it racked focus during production. It is best to do this quickly as a slow rack focus will take the audience out of the moment.
Filming in black and white when you have the option to film in color is never good because it lowers the possibilities that you end up having. You can always add a desaturate effect, at varying consistencies, in the post production phase. Most color effects should be done in the editing software and not actually with the camera.
To maintain energy and make the image feel more spontaneous you may want to make it look as though the camera is moving. This usually screams “hand held," but that has its own problems. The environment may not be forgiving, it may be hard to get stable enough images, and it is next to impossible to match perfectly with other angles. This can be added as an effect in the editing room, though it is not easy. To do this you set a number of in and out points on a set clip in the motion tab and then blow the image up slightly larger than it was originally. From here you then go to each in and out marking and have the image move in some different direction for each in and out segment. These should be very small segments and the movements should be incredibly minor. You are also going to need to look at the quality of the original image because you are increasing the size.
Editing can be the most creative process in filmmaking because you have more freedom for trial and error. Try to do what you can during production, but make sure you keep experimenting during post-production.