I have to admit, I'm a little confused by your question; and without knowing specifically how you want your images to look, there's very little anyone can suggest that may be of any real help. Have you ever produced images that met the standard you are aspiring to? I found the images on your website to be creative, imaginative and very well executed. I noticed that a good number of them were sort of "soft", but I have to believe that is intentional blur to create a moody/ethereal feel. I've tried NX2 with Lightroom and found it to be an just an extra step, and I could create the same results with adjustments in Lightroom. Others swear by NX2. It's a very personal decision. So specifically, what do you want to improve? There are numerous tutorials and websites available to teach the applications you use. Just google Lightroom and explore the Nik site.
I hesitate to mention Photoshop, and only do for the sake of completeness. I don't think you need it, again judging from your website, and if you feel bad now, learning Photoshop with its steep learning curve will only make you feel worse.
Workflow is highly individual, the path that is comfortable and makes sense to each of us takes to get from here to there. I believe you have all the tools you need judging from the images on your website, so let's go back to the beginning - the camera. Don't forget that the image you see on your LCD is a virtual JPEG with adjustments applied. So are you using good glass? Do you use a tripod as much as possible? As I said, without knowing specifically what you want to improve, no one knows where to begin.
Honestly, it sounds like you are really just in a "slump". I'd suggest staying focused, review the tutorials and websites. We have to be critical of our work in order to improve, but we can't let that criticism overwhelm us or prevent us from moving forward. Hang in there, dig into the tools you have, and work through it.
De l'audace, encore de l'audace, toujours de l'audace!