FOR ACTORS (AND WRITERS:)
WATCH OLD MOVIES AND TV SHOWS
... thats right. And I mean stuff made before 1989. Get used to it. You learn about acting, story telling, directing, and how to carry on a reasonably intelligent conversation if you know a little something about those who preceded you. If you grew up watching Roger Moore as James Bond, and think HE is the quintissential Bond, guess again. Watch the originals with Sean Connery- HE is Bond; Moore is a poseur.
If you grew up watching Family Matters or Home Improvement, watch I Love Lucy, The Honeymooners, and The Dick Van Dyke Show and All in the Family to see how excellent TV comedy can be.
Watch all of the AFI Top 100 films of all time. Yes some are in black and white, but YOU CAN DO IT. You'll be amazed what you can ideas or characterizations or visualization you can borrow from these performers, writers and directors... and how moved you will be by some of these classic stories.
Make it a point to keep current NOW. Watch 2 1/2 Men, as well as America's Top Model. You want to be really funny? Know whats happening in current pop culture, and, beyond that, know key pop culture iconia from the 20's, 30's, 40's, 50's, 60's, 70's, and 80's, too. I can't think of what makes the 90's distinct - I guess the dot com stuff - but the other decades sure are distinctive.
NOTHING SUCKS LIKE SUCKY SCRIPT FORMATTING
Your "spec script" is your calling card. I know, I know. Its the dialogue that counts, or the comedy, or the characters, or the clever plot. Yeah yeah yeah. But if the script looks like it was written by a beginner, psychologically a reader is apt to have lowered expectations. And when there are 100 scripts on the pile, you don't need any stinkin' lowered expectations (an homage to a line from Treasure of Sierra Madre - on the required viewing list!).
Final Draft script software program is the industry standard. It is little pricey. Second best, and at least adequate, for me, if you have Microsoft Word, is a free script template you can download called ScriptMaker. I have links to both sites on the right column. Or you can Google it. Or, since it's July 2008, should I start saying you can CUIL it. It gives you the basic sitcom and screenplay formatting, which you can of course adjust.
Few things are more disadvantageous than handing in a spec script with unprofessional formatting! It may not seem like a big deal, or your stuff can be genius, but psychologically, it screams AMATEUR! in the minds of readers and downgrades your chances, on a subliminal level. YOU HAVE ENOUGH HURDLES.