4. You Used Bold
Just don't use it. Ever (and many would argue with the same degree of severity that you rarely need to underline words, either).
3. You Probably Included At Least One Cliched Line Without Realising
Because we're exposed to movies in such high volumes, hearing those "cliched" phrases on such a frequent basis has largely desensitised us to them. The less of these things that find their way into your screenplay, the better. Take another look at what you've written, and see if anything seems familiar to you. If you feel like it might be a cliched phrase, or an overused one, or is similar to something you heard in another movie somewhere, scrap it. It's - quite simply - not the worth the risk.