See, the techniques you're using are great, and can be useful tools, but only if you put in the proper amount of effort and intent.

The real trick for maintaining stabilization in a dream is properly directing your focus and attention. If things start to fade, lock onto something in your environment and focus on it. Ultimately, though, you want to develop your focus so that you can scan your environment and focus on everything you see in a relatively short time. You'll find out for yourself why this is.

Good luck!