The usual shield construct is often referred to as a bubble shield, because it usually takes on the form familiarized as a soap bubble (but this is not a set rule). The shield itself is created through the use of visualization and energy manipulation. Visualize some of your energy in a bubble shell surrounding your entire body. To help this goal you may wish to send energy to the top layers of your skin for ease of energy use during the visualization. The colour of your bubble shield will be determined by your Internal Energies and the thickness will depend on the amount of energy sent out to create and sustain the shield. When visualizing for this shield keep a clear goal of what it should do in your mind; mainly it should keep outside energy away from you.
Your shield will last for as long as you maintain it. A shield will stay in effect until either it runs out of energy, or it is destroyed. This means that you should never assume you are shielded simply because you went through the motions of creating one sometime in the past. Unless you can see, or feel the shield yourself it is best to have a daily routine to upkeep it, by sending energy to it.