motivation and discipline are for me the most important things (and the instrument ofc) and it seems you have all already
what kind of music you want to learn? I'm just being curious
what instrument are you learning?
and for now I think the only tips I could bring are talk to your teacher, sometimes the teacher is not good for you but you think you are doing something wrong. A good teacher should motivate you to practice and play a lot at the end of every class.
At the beginning it may feel a little hard and boring since your learn the basics and your fingers are adapting to the new "movements". But again, motivation and discipline will pay off later on if you keep on practicing. Which leads me to my final point
PRACTICE, every day. You don't have to practice 3 hours everyday. At the beginning literally 15min will be enough, but try to practice every day of the week, (ideally 6 of the 7 days, and respect that routine, your day off you shouldn't even look at the instrument)
if that's too much at the beginning np, 3 or 4 days a week will do the work
ps one final tip, keep listening to the music you like / want to learn. It will keep you motivated whilst teaching your ear to pay attention to new and different parts of the same song / piece. Check covers of the songs / pieces you wanna learn, (not only of your instrument, but every other cover you may come across to)
oh and before I forget, you mentioned two things: you want to learn an instrument AND to sing, right? you'll be attending weekly classes of which? if you are only learning to play an intrument, there's hundreds of tutorial and videos to warm up your voice and learn how to contro yourl breathing. That's for a start
hope it helped you, you can pm me if you have more questions. I am a guitar teacher, my english is not the best, but I may help you get through a particular doubt if you cannot wait for the next weekly class
