So, I practice daily but I feel like there's a real plateau effect with everything I learn to play. Wondering whether is something worth reading out there that might help me overcome this?
I don't know if reading anything will help as much as simply messing around with your practice routine.
I can hit a plateau at almost any time, and what often works to break it up is to change in a big way the way I practice the piece (but not necessarily for a long time). One effective ploy is to slow down enormously for a few times through. Another is: if you have been using a metronome, stop; if you haven't been, start. Another thing I am finding useful is to practice at two different speeds (or more), but which are not pushing me very hard. Practicing just bits and pieces of the piece rather than going through it from start to finish each time helps, too. Getting deliberately silly with the music, and playing it a manner opposed to how you think it is supposed to go or with wildly and comically exaggerated expression can help. The old stand-by of practicing in rhythms is an old stand-by for a reason - it works. Another method is to practice just from one beat to the next beat, and getting that single beat's worth of music completely under control at around the speed you are aiming for. The do the same on the next beat. Don't put them together until you are utterly confident in each one separately. Then do the next beat. Etc. And another thing I have found that can help is instead of practicing the same things each day, set up an alternating schedule, so that you practice stuff every other day instead of every day.
Anyway, I'm sure you get the idea - if you feel you've hit a plateau, I think the thing to do is to somehow derail what you've been doing, and do something else, even if it seems like you are moving backwards for a while, or feels a bit alien.