Also for your last question; i would suggest adopting time frames as opposed to as you said “play a scale 10x” Its amazing how much progress you can make in only say, a half hour/day on one technique if you really concentrate while doing it and keep it up consistently (even just 15mins, the key is to focus on something specific. It’ll all come together in time.
Also *very important* Never compromise good tone production for speed or for any reason really, it should be priority #1 (Aaron Shearer has a good set that covers basics like posture, r.h. nails and free vs rest strokes) its stuff your teacher should be able to cover but supplements never hurt..
I believe the phrase “its not what you play but how you play it” applies more to classical guitar than virtually anything else (as we have such a wide range of options) so its good to keep that in mind.
Metronomes are always your friend during practice, whether or not you’d rather stretch a rhythm during performance. Practice vs performance “practicing” is a bit of a different mindset, logically you’d think practice is when you make more mistakes etc, but in truth its the opposite. It goes back to limiting your speed etc so when you rely on muscle memory it knows exactly what to do. And the guy above who suggested memorization first is 100% correct, your muscle memory is always the first thing that will fail you if you are very nervous when playing for an audience. However, it won’t fail if you’re able to visualize the notes and play from your brain and not your hands. (Im sure theres a better way to put that but w/e)
If you really Really want to learn a piece, try being able to write it out before ever touching a note on your guitar.Then slowly play it without ever missing a note, like so slow its almost unrecognizable. I personally find that a very decievingly difficult excercise, but it has a ton of merit to it. That may be a ways down the road when starting out, depending on how much theory you’re already familiar with. but it really is an immensly useful way to bring a tune to the next level. As well as if you or your teacher can analyze the chord progressions within songs (get him/her to go over it with you and understand the I IV V’s or whatever the case may be) it will make the memorization process far far less of a struggle. I also found it a ton of fun to start making sense of things beyond random notes and had many “eureka” moments during those sessions when the dots finally connected. Especially if you’re interested in learning and analyzing something like bach for ex. you’ll quickly realize that the rabbit hole goes far deeper than you ever imagined.
Theory also takes some practice and time spent applying it too, but its worth every minute, like when learning your multiplication tables as a kid theres a point it will become second nature, but these apply and will very significantly simplify virtually every single future musical endeavor you pursue, and very likely at the same time increase your enjoyment, due to a deeper understanding, throughout the entire journey. (it feels good to “get” why composers made/make the choices they do, which also gives you greater license in your interpretations imo) Theory is a really easy part to neglect on guitar, but you certainly don’t have to