You can probably bypass a bit of step 1 by doing a general overview of what’s needed to prepare and write a screenplay. This will usually mean attending a script course of some sort (McKee etc), and reading a few screenwriting books, perhaps even downloading a couple of your favourite scripts from Drew’s Script-O-Rama. But if you really want to get ahead, don’t skimp on step 1. For book writing, it’s widely accepted and encouraged that aspiring writers should have a passion for reading, and so the same should be for film & TV. We all love to WATCH, and this is an important part of the process, too, (to watch & consume a lot of film & TV) but we learn more by READING. After all, this is how your work will be judged, so it makes sense to swot up as much as you can. You quickly discover that your Shane Black-style and killer premise isn’t as clever as you once imagined.
Now, step 2. Writing. Start developing your ‘portfolio’. Shorts, TV episodes, feature specs, whatever floats your boat. The important thing is to write, and keep writing. Finished one script? Great, congratulations! But you need more. Rewrite the script. Start a new one. Improve your work, especially with what you’ve learned from the ongoing process of step 1.
I met a few students the other day to talk about what it’s like being a freelance screenwriter and one of their more pertinent questions was: “do you have a social life or how has that been affected by pursuing a writing career?” It may sound like a trivial matter but it’s not. The thing is, once you decide to give writing a go, a decent and proper go, your social life takes a big hit. You don’t really go out anymore. Friends and family are reduced to emails and phone calls. Not because you’re being rude but because you’re busy writing (and don't have any money, naturally). And here’s the crucial factor, YOU ENJOY IT. You don't mind. You don't really feel it because you're compelled to write or you're determined to succeed.
Janel Maloney, the actress who plays Donna in The West Wing, once asked Aaron Sorkin what he did at the weekend. He just looked at her and gestured ‘typing’ with his hands. To her, it was inconceivable to work so hard, especially at the weekend, but in truth, writers, and busy working writers, work all the time. Morning, noon and night. Seven days a week. Yes, it's difficult to fit in sometimes, and life can get in the way, but there's no avoiding the fact that if you want to be a writer, then you have to write something. Otherwise it’s just talk and bullshit and procrastination. Keep at it. Find the time in your schedule or tell your family/friends that they may not see you for a while. It's not easy, especially at the beginning, but it simply cannot be overlooked. That said, there's more, much more, to building your career than just writing.
Next up, step 3: networking.