Apparently claiming magic is frowned upon by the Instructables community.
I believe the following instructable will help to answer your questions.
Folding small models is, in many ways similar to folding regular sized models. Really there are two main challenges to it. First is paper thickness. We take for granted that paper is..well...paper thn! It makes it easy to fold because it is thin relative to the overall size. Once we get down to small scales the ratio of paper thickness to paper width is much less generous. Add to that the fact that each time you fold over you double your thickness and this is like folding a phone book.
I was considering demonstrating this through an interpritave dance, but I went for the instructional video.
Part 1: I introduce some basic ideas and fold the first large model
Step 1: The Problem of Fingers
This also makes it hard to demonstrate techniques because my own fingers get in the way of seeing the paper. You will need to practice this. It is helpful to practice folding without looking because so much of this will be based on your sense of touch.
I'm going to throw back over to the video here where you can see this on the first small scale model. The fox model is from Origami Omnibus by Kunihiko Kasahara, which has the full instructions and so much more.
Part 2: I go down to the smaller scales with a model of a Fox
Step 2: Smaller Is Thicker
With this next video we'll simulate a very small scale crane. It is good to see this here at the large scale to appreciate the problems you will encounter, but remember that at a smaller scale those imperfections will be less noticable.
Part 3: I go back to make a larger model using thicker paper to simulate the effects that will happen with the smaller scales
Step 3: Rolling Down the Scale
Try not to sneeze also. When your model is the size of lint, you will not get it back from a dirty floor.
Back to the videos where we go back down to successively smaller scales with a crane, a Loch Ness Monster style dinosaur, and a smaller crane. At the scales of the last crane things are just too small to make all of the fold for the full crane, so I make it slightly simplified.
As you progress to smaller origami go in this same progression. Work on smaller and smaller scales. As you encounter problems, practice at the scle where you are comfortable before pushing your envelope (so to speak) further.
Part 4: I scale down the crane model to small scales
Part 5: I go to smaller scales with a Loch Ness Monster style dinosaur model
Part 6: I make an even smaller crane model and conclude the series
I look forward to any comments! If you make some tiny origami of your own please post them!