Screenwriting is an awesome gig if you can do so professionally. Before you can do that you're going to have to write some scripts! True anyone can write a script, but not just anyone can write a good → compelling → great script in that order.

Even if armed with 'how to's' for scriptwriting or some experience in doing so behind you, it helps to know the terminology. If when talking to a producer or director would you know what they meant when they say what the writer will be 'Against'? What about a 'Blackout' or 'Character Arc' or a 'Bump' or have you encountered 'Development Hell'? Here's a link to a pretty good glossary covering a variety of terms often encountered during the scriptwriting process and during the negotiation and production sides.

http://www.screenwriting.info/glossary.php