Years ago, a writer friend attempted to convince me to write screenplays rather than novels. One of his arguments was screenplay writers had a better chance to make money. (A screenplay can either be sold or optioned repeatedly. A novelist isn't paid unless the book is published.)
I never completely took him up on the idea. My friend now lives in California and has sold and optioned several scripts. I've written three full-length screenplays, none of which have been sold or optioned, simply because I never submitted them.A short screenplay, "Cemetery," placed second in The Writers Place Short/Teleplay screenplay competition in 2004.
While I enjoy screenplay writing, I'll admit my actual output is relegated to this time of year, also known as Script Frenzy.
Does this mean I've eschewed writing novels? Not at all. But screenplay writing is an entirely different process, more restrictive even. And it's those limitations that actually make it more freeing.
What does this mean? Only write action, dialogue, and description on the page. The saying goes, "If it isn't on the screen, it isn't in the script." No internal thoughts. No camera directions.
Be aware if you read a script, either bought/downloaded from the Internet or purchased in a bookstore, these are usually shooting scripts. You aren't writing this kind of screenplay. Instead you would be writing what's called a spec script. This is a screenplay that isn't commissioned.
How do you write a script? Read both scripts and books about screenplay writing. You can download scripts for free from Drew's Script O'Rama. Learn the rules for formatting. If you become serious about being a screenplay writer, you might want to invest in formatting software like Final Draft or Movie Magic. (Both have free demos.)
Study books related to screenplay writing, such as Blake Snyder (Save the Cat!), Syd Field (Screenplay), or Robert McKee (Story). Other resources include Joseph Campbell's The Hero with a Thousand Faces and Chris Vogler's The Writers' Journey (based on Campbell's The Hero's Journey) as well as Script magazine and Creative Screenwriting.
By the way, these books can also help you write a better story, whether a screenplay or novel.
Okay, I have 25 days to write a 100 page screenplay. I'd better get busy. Meantime, if you want to try screenplay writing, I say give it a go. If nothing else, it'll give you a new perspective on your writing.