Sometimes, I will reference videos on youtube (pressing the spacebar like a spaz to play/pause the frame). Other times I will reference images and videos I capture myself, it all depends on your vision.
After you can ace the flipbook test, it's time to move toward the light-art animating. For starters you need a dark location - somewhere that has a unique view, or perhaps build it yourself? Up to you!
You'll need a DSLR, remote, tripod and light - I use Night-Writer because I made it for drawing with. First part is setting the scene - I like to scout locations in the day so I know exactly what I'm getting into at night. Often I will take phone pics to get a general idea of what angles I'd like to use later that night.
Once on location you'll get to the spot, set up your camera on a tripod, take the lens cap off and start to compose a scene using a high-powered light. Manually set your focus on the area you would like to animate around and set your camera to 'Bulb'. You may need to adjust your camera settings so that you can use the remote. After you think all the settings are correct, it's time to test it out - do something basic to start with and then adjust camera settings to get the right look you're going for.
Common settings for different lighting conditions:
City Lights: F.16-22 | ISO 50-200 | 100-150 sec
Full Moon: F.7.1-9 | ISO 200-400 | 150-250 sec
New Moon: F.16 | ISO 1600 | 50-100sec
Using your remote - trigger the beginning of the shot, then hop in front of the lens and draw each frame (I like to use a rock or something to mark where my character needs to be for each frame), slowly move your character and motions with each consecutive long-exposure (just like with a flip-book). Trigger your remote for the beginning and the end of each frame in the animation, I like to animate at 24 frames per second because I think it looks best. 24 frames is equal to one second of footage!
Once I have all of my frames, I will edit them using lightroom or photoshop so that they all look like similar exposures. After this, I open all the edited images in Adobe Bridge so that I can see the first frame to last frame files in one place visually.
I open the first frame in photoshop and then stack the next frame on top of the first into separate consecutive layers. Once I've compiled all of my 24 layers on top of each other, I open the 'Timeline' tab from the 'Window' top selection. There's a button that says 'Create Frame Animation' - click it.
You should see one frame in the timeline, but you will need to select the upper right drop-down menu, there is a selection called 'Make Frames from Layers'. Use that to have all of your layers import to the timeline.
Now it's time to select the frame rate, adjust the delay as needed to make for the smoothest animation. I like to use a .06 sec delay on each frame.