Sometimes it's just slow. I was stuck around 42 seconds or so for several months, and lately I've improved to around 35-38. The line is probably in a different place for everybody, but as a fellow slow cuber I am convinced that at some point there's just an element of natural ability that's required to be really fast. I'm sure that the vast majority of people can be faster than you and I are right now, but I know not everybody can be world-class. Some things that helped me were doing a little OH solving, and solving bigger cubes (mostly 4x4). What algs do you know? If you're working with a 4LLL It seemed to me to be worthwhile to learn full PLL. Definitely full PLL before full OLL. It's also possible if you're working with algs for f2l you might be taking too long with recognition. I don't know, I've never really used specific algs for f2l since I switched to CFOP. You might also try messing with different methods. I've heard a lot of good things about Roux, though I haven't learned it yet. ZZ is also fascinating. And although I'm hopelessly slow at it but I've been having a lot of fun with Petrus the last few days. I'm mostly working on Petrus to help with FMC.