If you see one film this month, make it Miss You Already.

Starring Drew Barrymore and Toni Collette, it explores the relationship between two friends when one (Collette) is diagnosed with breast cancer. Once you've watched it (and probably cried a lot) donate to Breast Cancer Care at breaststroke.org.U.

To mark the film's release, we asked the Miss You Already's writer Morwenna Banks to give us her tips on how to write a screenplay. Read her advice below...

Drew Barrymore and Toni Collette star in Miss You Already

"In the much overused words of Oscar winning screenwriter William Goldman, “Nobody knows anything…”. Mr. Goldman coined that phrase in his 1983 classic handbook Adventures in The Screen Trade. He had a string of hits behind him among them  – Butch Cassatt and the Presidents Men. I, however, am writing these practical tips with considerably less success and experience but I have been writing for several years now and I hope my random tips encourage anyone who is thinking of writing a screenplay. If you have a story you want to tell, then for goodness sake, try to tell it. You might as well. Because you never know."

1. "Read the screenplay of a film you really liked – just to get a sense of the size and shape of it. I once found a copy of the script of Four Weddings and Funeral and just seeing those opening pages of expletives encouraged me. Then download a scriptwriting program like Final Draft so that what you’re writing at least LOOKS like a screenplay."

2.  "Don’t be put off if you run out of ideas, just keep going – even if you think it’s rubbish. Edit later, but do try not to keep reading emails or buying ‘essential’ luxury items on line. Only check email when you take a break. Try to last longer than five minutes without taking that break."

3. "Unless you have someone trusted and very experienced to read your work – don’t give it to anyone until you are happy with it and it reflects what YOU want to say. When they read it - If they don’t like it – stop being their friend immediately. I’m joking – but don’t let them put you off."

Drew Barrymore and Toni Collette star in Miss You Already
4. "It is good to have a sense of the three act structure and to have a rough idea of where your story will end up. But don’t freak out if you veer off that path when you are writing. Some films freewheel."

5. "Always try to express things in an original way. Have your characters say things that only you could come up with. And remember film is a visual medium and so much can be conveyed with subtext and physical action."

6. "Go back and watch your Favorited films. Remind yourself what it is you love about them. I have so many top picks but a few I revisit for inspiration in terms of dialogue, direction and originality are: Within and I, Annie Hall, Napoleon Dynamite and Eternal Sunshine of the Spotless Mind (careful though - don’t get depressed and think ‘I’ll never write anything this good’)."

7. "Create a nice environment to write in; my desk is a simmering rubbish tip but I always light a candle – it helps me focus and smells nice. Give yourself treats. No-one can get through a day of writing without incentive. Tea , Coffee, crisps and biscuits – all essential. You NEED them. And what’s more you DESERVE them because you are going to write a brilliant film."
Miss You Already is out in UK cinemas on Friday 25th September