I recommend a book called
The Script is Finished, Now What Do I Do? by K. Callan. She's had a great deal of experience in Hollywood as an actress and writer of advice books.
http://www.scriptsales.com/BkRvwScriptFinished.html
I also recommend Alex Epstein's
Crafty Screenwriting. An early version is online:
http://www.teako170.com/faq.html#spelling
If this is your first script, it probably has too many flaws to meet professional standards. It's not impossible to sell a first script, but it isn't very likely.
If you've got enough hustle and salesmanship, you can get read by important people fairly quickly. If these people see bad dialogue, weak plotting, poorly drawn characters, inept format etc., they will chuck your script and never deal with you again.
Your growth process as a screenwriter could be accelerated if you come to the craft from some other genre of writing or performance, where you had to learn the basics of plot, dialogue, and characterization. Perhaps you've been a successful playwright or popular fiction writer. Perhaps you've written feature articles for national magazines. You may have reviewed hundreds of films for a major newspaper, or performed as an actor in everything from Shakespeare to August Wilson. Maybe you've been on the road doing killer stand up for years, and you're ready to move into features in a big way. You could have written and drawn a daily comic strip that's become the favorite of the young and the hip.
If you haven't had experiences like this, your chances of writing a saleable script on your first try are slim. Much more common is the bright, talented writer who keeps at it for years, writing five or ten scripts, getting feedback, joining workshops, learning about acting and filmmaking, finally arriving at a point where her work can inspire the enthusiasm of experienced film people.
This doesn't have to be you. Some people do break through right away. The risk you run, if you aren't golden, and let's face it, most of us aren't, is that you waste good contacts on bad work.
You should at least seek out the opinions of some experienced people, not your friends or family members, who can evaluate your work with some objectivity. Have you had a reading with skilled actors, or attempted to shoot a few scenes on video?