Then greater the range of emotions you play, then better. It's like an octave of a singer; someone takes two, and someone all four. Find (or create) a monologue in which for a few minutes (no more than 3 minutes), you will be able to demonstrate tears, despair, happiness, love. You may need a partner who will be serving replicas behind the camera. Or you can do it alone. If it is enough to show emotions for a video card, it can be laughter, surprise, fright, smile, for "video emotions" you will have to dig deeper and pull out genuine feelings and suffering.
How to play and live strong emotions of all actors are taught in theatrical schools. But there are actors-kids and they need to have the basic skills in order to record such a video. If by script, the child should cry in the frame, the Director usually asks him to remember strong personal experience. Such memories are called triggers. This is a kind of triggers for the release of emotions. "Video emotions" can be recorded both in a professional Studio and at home on camera in daylight, picking up a neutral background in advance. The street is not good for shooting, a lot of noise.
Also make photosnap emotions; they are also useful for portfolio. Just do not grimace at the camera; emotions should be easy to «read» from the photo. If your fright is similar as surprise and passion, you obviously have something overdone. Standard «map of emotions» includes from 7 to 12 different conditions. Usually this fear, anger, joy, sadness, revulsion, expectation.