The first part of the operation, at its most basic level, involves the 78 Tarot cards being split into four piles, those piles being turned over and the bottom cards analysed to tell a ’story’. Some people like to use a significator to represent the person they’re doing a reading for. Whatever pile the significator turns up reveals the nature of the question being asked.
However, I don’t use a signifcator, and to explain their role would take too long.
The real key to doing the OOTK is to ignore the cards and look towards the Elements of those cards. It’s really much more of an act of imagination than anything else. I suppose the main thing to keep in mind is that this spread, from what I know, originates with the Golden Dawn and they have a particular way of interpreting the universe; the forces of nature and their representations. In fact their rituals were based upon this (as are most rituals based on some sort of Universal paradigm).
The first thing then is to think of the OOTK as a ritual (with both its active and passive phases) and like all rituals it should be fun. I know the Golden Dawn, certainly when I was practicing it, seemed to be all about hard work. I speculate that this work ethic has been handed down to the OOTK. Rituals are fun; the opposite of the work ethic. They’re meant to be enjoyed so the main thing, when practicing the OOTK is to have fun.
The best way I know to do this, especially when it comes to telling a story based on the first part of the OOTK, is simply to go crazy with your imagination. There is no right way to interpret the cards. If the four piles are all water then maybe create a story based on relationships; psychic development; creativity and inner reflection. If all the Elements are present apart from the Fire Element then perhaps (Fire being responsible for making things happen) the persons stuck in some kind of a rut. Let the images of the cards jump out of you to provide the characters or themes for your story. The final thing to do is use the divinatory meanings, or DM’s of the cards.
Let’s look at an example:

Okay, the first thing to kick start the imagination must be the absence of Air. We know then, that there will be a lack of control or intelligence in this story. We also know, by inference, that this story will play out, with this person being out of control in certain key areas of their life.
Let’s take a quick look at the cards:

The Emperor is the card that immediately jumps out at me. Now we can see where the lack of control is – somebody else controls the client! The fact that there are 2 twos (2 Wands, 2Cups) indicates a relationship, and the 5 of Disks the loneliness that results.
I’ll leave it up to you to figure how you would explore the clients possible ‘options’.
TIP: Can you see why the Emperor, in his need to control, is actual very disempowered Elementally? Oh, and don’t forget the 5 of Disks.