I can’t stop staring at Thea Sharrock. She’s only 30 but, with the enormous amount of high profile work she’s done over the past seven years and the huge acclaim she’s received for it, I’m shocked (and a bit jealous, if I’m honest) that there’s not one line or wrinkle etched on her face to show it. In fact, she’s not entirely dissimilar to Zara Phillips - all wide blue-grey eyes, creaseless, creamy complexion, gleaming white teeth and shoulder-length blonde hair.

It must have something to do with her attitude. She saunters into the Almeida café as if she has all the time in the world, dressed in her simple blue jeans, a regular white t-shirt and devoid of any make-up. There’s no sign of a harassed mum of one 19-month-old baby or a high profile director. Sharrock is completely unaffected, pensive, honest, open and oozing calm – a wise old soul in an impossibly young body.

Although she may have always been this way, it appears to me that Sharrock is a product of her environment. Describing the skills needed for directing, she cites: “A level headed sense of diplomacy when you’re dealing with actors. You need to be calm and brave, in order to stick by your ideas. You’ve also got to be a bit of a shrink because you need to understand both the character you’re trying to get someone to portray and also the actors, in order to get them to portray it. And you’ve got to have a great dollop of ‘It’s only a play’. There are no wars being won or lost. It’s alright if it’s not the best thing that anyone’s seen ever, as long as we’ve done our best.”

Embodying all of this has stood Sharrock in good stead. Since emerging from Oxford University, her feats include winning the James Menzies-Kitchen Award for young directors in 2000, which resulted in her first professional credit – directing Caryl Churchill’s ‘Top Girls’ play at the Battersea Arts Centre theatre.

In 2001, aged 24, she became Britain’s youngest Artistic Director (AD) at the Southwark Playhouse – a role where ‘the buck stops with you’. “All the decisions from what goes on stage, to what plays you’re going to direct, to how the ticket system is run rests with you,” she laughs. Three years later, she was snapped up by the Gate theatre as AD, and remained there until February 2007.

“If you’re in it for the glamour, turn around now. I sit in the dreariest of rehearsals rooms laughing about the glamour of it all.”

Her latest project, Caryl Churchill’s ‘Cloud Nine’, which opens at the Almeida later this month, was confirmed in May – a relatively short preparation period in the theatre world. She immediately hired her creative team, cast her actors, and got down to the serious business of directing… Which is what, exactly?

“It’s very strange, even my friends can’t get their heads around it. But my dad summed it up quite well. He came to see a new play I directed, got there a bit early with the text and started to read it. And he just couldn’t believe the difference between reading it and seeing it on stage with the lights, sound, actors and costumes. That’s what I do. I bring the playwright’s work to life with actors as tools.”

According to Sharrock, a director needs three things. First: “The best possible creative team you can have because they are your allies and the people who will be creating the physical world that your actors are going to be part of,” she says.

Second, a good relationship with the artistic director of the theatre. “They’re the people you look to for both help if you need it or constructive criticism because it’s their building and they care as much about the process and result as you do.”

Finally, actors. “My main responsibility is working and rehearsing with actors on set so that everyone not only knows their lines but speaks them as if they were the person. And that doesn’t happen overnight.”

There are two main types of directors, according to Sharrock - those who visualise everything in advance and have it all exactly that way, and those who are more ‘you bring to me what you want and I will guide’ style. Sharrock is very much the second.

“You have to have enough of a vision so that, if anyone comes to you, you can give them direction. But the most exciting part is when an actor comes with some decisions made and you start that journey together. It’s about making it believable so that when people come to see a show, they completely believe the performance. If they don’t, it’s as much my responsibility as it is the actors. That’s what I’m there for.”

And there are plenty of occasions when theatre falls down. “It’s very hard to get right. Nine times out of ten, it can either be boring, disappointing or unbelievable. But, when it is right, the feelings created and that connection with the audience can be so real.”

“It’s about the right combination of talent, luck and perseverance. If you have that, and want it badly enough, you’ll succeed. If you don’t, you probably won’t.”

It’s this Holy Grail that keeps Sharrock motivated - not the glamour or money. “If you’re in it for the glamour, turn around now,” she hoots. “I sit in the dreariest of rehearsals rooms laughing about the glamour of it all.”

The stability? “If you’re lucky, you know where your next job is. Generally people will come to you with projects. Sometimes there isn’t one and you have to look.” Even then, the money isn’t big. “By and large, it’s terrible. A West End hit with a big royalty goes along way. But working in the subsidised arts is very hard. You have to be very lucky to make it.”

To succeed in the industry? “It’s about the right combination of talent, luck and perseverance,” she says. “If you have that, and want it badly enough, you’ll succeed. If you don’t, you probably won’t.”

In many people’s view – including director Peter Hall’s – Sharrock is already succeeding. To this, she merely admits to learning a lot throughout her seven years. “In the beginning, I went in with huge enthusiasm to ‘go do it!’ but, like everything, you gain experience, learn the tricks of the trade and see that there are downfalls.”

One such downfall can be reviews – things which Sharrock no longer reads. “I’m very realistic about how useful they are and the affect they can have, but they can be incredibly painful. So I only get a feel for them now. Even the ‘amazing’ ones are never quite as amazing as you expect.”

Another challenge is balancing family life following the birth of her baby in 2006. “It’s very hard. Your work is incredibly demanding and you can’t pick and choose your moments with parenthood. But it’s been a huge life experience which has made me a more interesting person. And all you have as a director when you walk into a room is what you know and what you’ve gone through.”

Her future aspirations include film directing, which she says intrigues her though ‘I’m in no rush’. Beyond that, she’s decidedly vague. “I’ve no aspirations because they tend never to work out if I do. I’ve always sort of lasted on a wing and a prayer, so I hope that continues.”

Cloud Nine is showing at the Almeida from 25 October to 8 December. Tickets range from £6 - £29.50. To book, call the box office on 020 7359 4404.