What makes a great script?  A riveting story – or memorable characters?  You may say, both.  But for the star whom you want to attract to your script, only one thing matters: a great role.

Seen from that point of view, you might want to ask yourself whether your script is not just ‘a good read’, but offering something that’s important to an actor.  Because like it or not, without stars attached, your script is unlikely to get made.

The question is, what are actors looking for?  In my experience, usually not anything they’ve done before.  It’s amazing how much more easily you can get the attention of an actor or their agent if you are offering a new challenge.

Of course some actors really are types, and are resigned to that fact.  It never bothered Cary Grant – why should it bother Tom Cruise?  Morgan Freeman once played a bad guy who got his comeuppance – preview audiences were so horrified, the studio recut the ending.  Now Freeman’s resigned to playing nice guys.

So apart from a new challenge, what else are actors looking for?  Fortunately, the answer to that is the same answer to what makes a riveting script.  Difficult challenges, agonising dilemmas – create characters to die for.

The protagonist’s dilemmas are what invest every twist and turn in the script with not only narrative suspense, but emotional impact too.

Dilemmas are not just thrown up by plot, they’re at the very heart of character.  Your protagonist may look like you or I; but beneath the surface, passion, guilt or rage flow like molten lava, threatening to swamp their nobler nature.  Keep applying the pressure – and sooner or later, the volcano’s bound to blow.

The longer you hold off the inevitable, the more the actor has to work with – just don’t forget to give them the big, emotional scene that provides the payoff.  I call it the ‘stand up and cheer scene’ – the scene where the heroine faces up to her dilemma, makes her decision and acts upon it.

Why have audiences been so fascinated by the character of Andy Dufresne in ‘Shawshank Redemption’ – so much so that the film shows no signs of exhausting its cult success?  Maybe because we can all identify with the struggle to keep hope alive in the face of ever-present fear.

You might ask yourself whether you have taken your character, within the credible limits of your story, to the limit of their endurance.  Have you tested their mental, physical and emotional limits?  If not, then you probably haven’t offered something special to an actor.

What makes ‘Casablanca’ an enduring classic?  It could be many things: the romance, the thriller plot, the comedy.  But my money is on the character of Rick: the cynical, hard-bitten, charismatic bar-owner who undergoes one of the most marvelous transformations in the movies as he sets aside his self-pity and commits himself to a greater cause.

From the beginning, we feel that potential within him.  We feel the struggle of a man who who has created a shell to prevent himself being hurt.  Actors love reaching within a character to find something else: something the drama will bring into the light.  No wonder actors say they work “from the inside out”.

Whatever cause a character may choose to fight for – in the end, it has to get ‘personal’.  When Oskar Schindler risks all to save the Jewish workers who built his fortune, he doesn’t do so because of politics or ideology.  It is simply that those individuals have come to matter.

But a good ‘character arc’ is not all that actors are looking for.  When characters struggle with great dilemmas, the audience are held in suspense until the final frame – which way will they go?  Is it Jekyll – or Hyde who’ll win out?

A fine example of this is in ‘Donnie Brasco’, where Johnny Depp’s undercover cop lives his ‘role’ in the mob almost too successfully.  This conflict between his new ties and his integrity as a police officer threatens to tear him apart – and keeps the audience guessing.

When assessing the marketability of your script however, it’s not just the leading roles you need to think about.  A common fault is to have too many supporting roles, none of which are substantial enough to be ‘castable’.  By ‘castable’, I mean having a sufficent arc to make an actor of the highest rank want to play them.

Try, whenever possible, to ensure your supporting roles have an ‘identity’.  That means you can imagine (even if we don’t actually see it on-screen) their having a life of their own – that they don’t just exist in relation to the leads.  Actors are looking for the scene where they get to ‘make a statement’ about who they are, and what they stand for (dramatically – not literally, of course).

You should give every character something to separate them from the crowd.  Try covering the character names as you read through the dialogue in your script – do they have their own unique voice?

The role of Ugarte in ‘Casablanca’ lasts barely half way through the first act.  But in that span of time, Peter Lorre runs the gamut of emotions from triumph to complacency then despair, making him one of the most memorable characters in the film.

Orson Welles’ Harry, the antagonist in ‘The Third Man’, doesn’t even appear until the final act – but the elusiveness of his character makes Harry the best role Welles ever played (and that includes ‘Citizen Kane’).

A great cameo can secure a name actor whose appearance, no matter how brief, can lift the profile of your film. ‘Tarantino gifted a great cameo to Dennis Hopper in ‘True Romance’, courtesy of Christopher Walken; and in ‘Pulp Fiction’ Walken got payback.

Two unforgettable characters, one scene – one monologue each.  Both encapsulating the themes and creating (arguably) the most iconic moments in either film.  Get your characters, story and theme working in synch and actors will be fighting for your roles.