At the time, Kirk Douglas, with whom Kubrick worked before, had brought him in to finish the over-budget, flailing Spartacus; it was a film that would mark a turning point in his career. It was the first and only time he worked as a hired gun for a Hollywood production, and also the start of his wonder years, with Lolita appearing two years later. Kubrick was entirely self-taught, starting as a still photographer, but before Spartacus, he already had Fear and Desire and Killer's Kiss, two apprentice films, under his belt. He had also made the incredibly influential heist film The Killingas well as Paths of Glory, which some call the greatest anti-war film ever made. 

In December of that year, he gave his thoughts on filmmaking toThe Observer Weekend Review. Here's just a few:

Don't go in with preconceived notions

The making of any film, whatever the historical setting or the size of the sets, has to be approached in much the same way. You have to figure out what is going on in each scene and what's the most interesting way to play it. With Spartacus, whether a scene had hundreds of people in the background or whether it was against a wall, I thought of everything first as if there was nothing back there. Once it was rehearsed, we worked out the background.

The best plot is "no plot" 

I think that the best plot is no apparent plot. I like a slow start, the start that gets under the audience's skin and involves them so that they can appreciate grace notes and soft tones and don't have to be pounded over the head with plot points and suspense hooks.

Making a movie is kind of like getting naked

When you make a movie, it takes a few days just to get used to the crew, because it is like getting undressed in front of fifty people. Once you're accustomed to them, the presence of even one other person on the set is discordant and tends to produce self-consciousness in the actors, and certainly in myself.

"I like a slow start, the start that gets under the audience's skin..."

You don't have to succeed; just don't fail

The important thing in films is not so much to make successes as not to make failures, because each failure limits your future opportunities to make the films you want to make.

Never explain

I think it essential if a man is good to know where he is bad and to show it, or if he is strong, to decide what the moments are in the story where he is weak and to show it. And I think that you must never try to explain how he got the way he is or why he did what he did.

'Nuff Said. Check out the rest of his notes here

Source: The Kubrick Site-Kubrick's "Notes on Film"