tyler, if you are struggling to get words on the page then read Vicki King's
How To Write A Movie in 21 Days. It's geared towards screenplays but you can use the general idea for other forms too. It won't make your work good, but if you allow it to it can help you get things down on paper a lot faster. I did it when I was 17 and I wrote the first draft of a screenplay in 10 days (the book says 7, so really I failed!) and I was typically disappointed if I didn't hit about 1,000 words an hour.
Mental blocks are just that, purely mental. If someone says they don't know what to write I immediately call bull**** and tell them they're doing it wrong. We stop ourselves from writing for a myriad of reasons, most of which are simply borne out of over thinking it (as in, 'I can't write that, that sucks' or 'that doesn't make sense' or 'I hate myself, this is never going to be good' etc). That book helps you to stop thinking and start writing.
In a screenplay (and in my opinion pretty much anything written of significant length) nearly all the thinking should come before you start writing so that you know your story completely; you have the world, plot, characters, scenes/chapters etc all sorted and if anyone asks you any question about them you can answer (although be careful to use this stage as an excuse to not start writing) and so when you do write it should be easy. For example, Ferris Bueller was written in 6 days and barely changed from the first draft.
So:
1) Figure out the story you want to tell; what's personal to you.
2) Research and development: create your story; think about the world, characters etc. Use as many index cards, pieces of paper, whiteboards or whatever you need/want as necessary.
3) Stop thinking, start writing!
4) Start thinking again to fix your pile of **** (and let's face it, first drafts are nearly always bad).
Sorry for the derail.