I wanted to be an actor at university but realised I was only a mimic. Directing appealed to me because of an urge to tell stories - or maybe it's all about control and wanting things my own way. Radio was a very exacting medium to direct in. It taught me about the importance of rhythm, which is so important in radio and in film, too; how to regulate the flow of information and moods. Television was another training ground. It gave me a proper discipline when it came to directing for film.

The one complicating factor in film is that money is involved - the film's investors - and they have a say in casting and the final shape of the movie. That's fair, but there is argument. It's rare for a director to be taken off a movie anyway, and actors tend to be loyal to their director.

Shakespeare in Love had been around for five years by the time I got to it. It had collapsed after Julia Roberts had pulled out of and it was a leap of faith for Universal to take it on - indeed to take on any film with Shakespeare in the title. []I knew Tom Stoppard's work and have been around Shakespeare all my life. I knew I would enjoy it and people like me would enjoy it but didn't know if it would “travel”.

The rushes (the scenes shot and viewed day by day) looked very peculiar - often they were just shots, and I had to have faith in my vision that this fragmented thing would cohere.

Tom Stoppard and I changed the ending and changed the changed ending until we were happy. That relationship between director and screenwriter is crucial, as is the director's relationship with his cinematographer. I like to keep the writer as (metaphorically, at least) close to me as possible. I'd fax Tom at night asking for three lines and in the morning there they would be.

The director also needs to let the actors know exactly what he is doing: why the camera is where it is, why that particular shot is central to the film. Actors need to be really supported. Some are resolutely independent and I've always been amazed by actor-directors because how they monitor themselves is really impressive. I have never worked with actors who are diva-ish, but famous actors do have a special charisma and it is magical to watch them turn that on.

The job is also pretty technical: you've got to be aware of the camera, lighting, movement, but you also have experts all around who are your eyes and ears.

Directors always want more time. The job description should read: “To get as much material, and as much time to perfect that material, as possible.” That can become a monstrous self-indulgence, and since Heaven's Gate [Michael Cimino's notorious movie that went massively over budget and bombed at the box office] you can't get away with it.

One of the most important people is the first assistant director, who schedules the shooting of the film. The phrase I dread hearing is from them is: “You're spending too long on this scene. It's time to move to the next set-up.” With experience I hope I've come to know when I've got the right shot - you trust your actors and your own eye.

At the end of shooting you show a cut to the studio and to the producers and investors. There is an adversarial relationship there - the director has to work hard to maintain control over his or her vision. But it's good to be challenged and for the material to be interrogated.

The mystery of the editing process, of being in the cutting room, is that you invariably discover something you didn't know about the film. It gives something back to you that is utterly unexpected. Editing is also an important process because inevitably your film is too long and needs to be cut. I rather relish the argument and having to put my point of view and justify it.

The hard thing is showing it to a test audience. Every director finds it tough because a partisan producer will jump on one audience remark that they want to emphasise themselves and say: “You see, they found that scene hard or rubbish too!”

You could say now is a good time to be a director. It's not an expensive medium these days. You can film something cheaply and put it on the net. Write if you can write, perhaps start with a short film. Understanding how a script works is vital, but something often taken for granted. You could try film school and work experience, though apprenticeships on sets are few and far between. Have tenacity. Keep going.

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