In order for your practicing to be truly effective and a true measure of how well you are progressing, you must use a metronome. Metronomes are like your personal coach in the practice room. They force you to maintain a uniform standard throughout your practice time.
Let's say you just got a new piece of music and you are anxious to get it down. You would like to play it perfectly as quickly as possible; I'm going to share from my experience a great way to get there!
Step 1--Right hand Alone
First you need to master the piece hands seperately. Let's do this by starting with the last measure of the piece or movement on the right hand. Setting the metronome at a pace slow enough to make the piece easy, play the last measure alone. Repeat a few times or until it feels solid at that tempo. Now play the second to last measure into the last measure. Third-to-last measure to the end, etc. until you can play the whole right hand part beginning to end at that easy tempo.
Step 2--Left hand Alone
Repeat Step 1 with the Left hand.
Step 3--Hands Together, One measure at a time
Now it's time to put the hands together at that slow tempo. This time, let's start at the beginning. Basically, you will be playing a measure, then resting for the length of a measure, then playing the next measure, then pausing, etc. (I leave the metronome on all of the time) This gives you time to prepare for the measure to come before you have to play it and increases your chances of playing it correctly. Keeping the metronome clicking at a tempo that makes the piece pretty easy to learn, get your hands positioned for the first measure, and GO! As you play each measure, be a stickler! Sometimes it sounded ok, but you know it just didn't feel solid--wait for a measure, then repeat until you are happy with it before moving on.
**Before step four, do this step again only with a 1/2 measure rest inbetween measures, then again with 1 beat inbetween measures.
"Is this supposed to be a fast way to learn music?" Well, it doesn't feel very fast, for sure, but if you see this all of the way through, it is the fastest route I know to a very solid foundation for a piece because it gets the FINGERS to learn by MUSCLE MEMORY. Once you get the notes, fingerings and rhythms your mind will be free to think about other elements of the music.
Step 4--Hands Together, Two Measures at a time
Now it's time to add to the challenge! From the beginning of the piece once again, with the metronome clicking at that same tempo, you are going to play two measures at a time followed by a full measure of rest all of the way through. Thought you were doing pretty well, right? Believe it or not, this can be a pretty challenging new addition! Remember to repeat a pair of measures if they didn't go well. Just count out the measure of rest and play it again instead of going to the next one. When you're happy with it, move to the next one.
**Before step five, do this again only with a 1/2 measure rest inbetween pairs of measures, then again with 1 beat inbetween pairs of measures.
Step 5--Hands Together, The other two measures at a time
Ok, this one is fun. This is essentially the same as step four except you will start with measure 2 instead of measure 1. So now you are pairing 2+3, 4+5, 6+7, etc. This step knocks out the threat of unpracticed TRANSITIONS.
Step 6 --Hands Together, Four Measures at a time, 8 measures, 16, whole piece
Now we come to the final steps of learning the piece. Continue to use the same idea of inserting a rest measure but make your "Play measures" longer and longer! First play four measures at a time all of the way through adding the full measure of rest inbetween, then eight, then 16, until you have the whole song.
You should now be able to play through the entire piece smoothly and correctly at the tempo you've been practicing!! Good job! From this point as you continue to learn the piece, you will need to increase the tempo of the entire piece. Any time you are increasing the tempo, be sure to bring everything up at the same time by running through a mini version of this technique at the new tempo--and never speed up by more than a few bpm at a time.