A little music background: I played the piano since the summer before sixth grade. I took private piano lessons with various teachers (not the kind you might meet at a conservatory of music or a college) until I quit about five months ago. Now I'm on my own, and I'm going to teach myself to become a virtuoso pianist.
The daily practice routine I'm following is 1) Hanon exercises 2) scales and 3) three to four piano pieces. Also, I've recently taken the position of piano accompanist for my high school's choir, so I have to learn piano accompanist parts in addition to my current routine. The musical pieces I'm currently learning aren't easy though (Hallelujah for example).
I need some advice on how to practice difficult pieces and what is an effective practice routine. I'll really appreciate it if anyone can give me some good tips!