Everyone has a different style/method/preference when it comes to writing, so clearly you need to choose something that works for you. That said, if your current way of doing things seems to have you stuck in a rut, it may be time to try something else and see how the "new way" goes.
If you have the whole story in your head but you're having trouble writing that next word or next scene why not write something from the end...or from the middle...or basically anything other than the next scene. If you're not comfortable skipping ahead like that then try writing something that's about a single one of your characters; a dossier or even a rambling description of the person (something along the lines of how you'd describe a friend to someone who doesn't know the person). If you already have character histories written then try taking a break from this particular story and write something else entirely---pick a word and write a scene or story using that word---anything to get you writing. Sometimes while you're in the middle of writing something else the inspiration for your WIP will fight its way into your mind---then you know it's time to work on the WIP.
The most important thing for you to remember is that YOU ARE NOT LAME. (And there we have the reason that I am not a journalist; I habitually bury the lead.) There are millions of people who talk about how they would love to write a novel some day and you're a giant step ahead of them, you're in the process of writing one. It is, however, a process. Sometimes it's fun, other times it's maddening, but it's always a process. Be patient with yourself. Remember ALL writing is writing (even forum posts), pretty much none of it is perfect (even after editing), and that's okay (really, it is).
The best writing advice I ever got was an offhanded comment a friend made to me while I was in the feverish midst of writing my current WIP. I sent her some chapters to read and I was babbling to her about plans to fix this or edit that and she took a deep breath and said to me "stop worrying about all that, JUST GET IT ALL OUT". She was right. You're always going to go back and change things; tweak this, edit that, cut a scene, add a scene, change a tag---there's plenty of time to do all that. Again and again, and probably again. Then probably a few more times, just in case. (To paraphrase Nathan: keep polishing it till it shines like the top of Chrysler building then go back and polish it again, you missed a spot.) In the first draft stage the most important thing really is to get it all out. Get it down on paper (or screen) where you can go back and look at it later with fresh eyes (and still later with bleary eyes). There's plenty of time to put pressure on yourself to perfect it all down the road; save some stress for later. ;)
Passionate Plume 1st Place Winner 2012 - ALWAYS YOU
Published with Ellora's Cave, Turquoise Morning Press & Samhain Publishing