First, select an image to work with. I recommend you a black background image so every illumination are more emphasized. After this example you can try with other backgrounds and with other color brushes.
The stroke path.
Use the Pen Tool to draw curves that move along the object. In the example, you can see the way of making an outline or path with only 3 points. (It is shown with white background to be easily noticed). You have to click first at the bottom, click and loosen the mouse button. After that, click for a second time in the middle of the object and hold the click and drag the mouse creating the anchor point handles. Finally, make a last click at the top and loose the mouse. For those having already practice with Pen Tool, it becomes easier.
Make several curves wrapping the object from several sides with the tool.
Turn the stroke path into a brush.
Once you have the object ready, select Brush Tool and create a brush (a brush of 30 px in a picture of 220 dpi and 4 inches wide was used for the example). Use a color that stands out of the background, create an empty layer which will be the brush layer, go to the Path panel and select the panel you already created. The second knob at the bottom, from left to right, is to turn the path (Stroke Path) into a brush, but before pressing it, hold the Alt key in order to have options available.
When you click, a dialogue box is open from which you can select the tool you want to turn the Path into. Select Brush and select the Simulate Pressure option that makes the path to end in a point.
In the picture above, the merge way was turned into Color Dodge and the Inner and Outer Glow effects so to create a better illumination effect. You may try different ways of merging in order to create different effects.
We will now add more brushes so to create more light effects. We first add a second brush, but thinner, to go with the first one. Create a pencil thinner than the last one (30 px in my case) and turn it in a new layer, into a brush the same way as you did in the former step. In my case, I did not add layer styles this time and it is gray. You can try different colors and styles also.
Create a brush of the same size as the first one, as a first action (30 px in my case); go then to the Brush panel so to configure the particles. The first adjustment to be changed is Spacing as a brush is a set of points along the path and this adjustment separate each of this points.
The second adjustment we change is Size Jitter which is inside of the Shape Dynamics one so each point have a different size between the others.
We finally change the Scatter value which is inside the Scattering option.
It will result in a pencil as the one at the bottom.
If you want so, you may add other elements as in this way I added iPhone applications symbols. The result is very interesting and you can try with people, cars or other elements.