Coming back to writing articles with a short list of warm ups you can do to get the most out of your practice. Like exercising, doing gymnastics, or running; you should do warm ups beforehand so that your mind, hands, and arms are reading to play some music.
1. Scales - I wrote another article on how knowing and practicing scales can make you recognize and play certain patterns in a passage of music much better. Scales are also beneficial in helping your fingers move and stretch. Scales involve playing a series of notes with a certain fingering, so warming up with scales will help you play up and down the keyboard more effectively. Scales can be played in parallel (both hands playing the same notes an octave apart), contrary (in opposite directions), or in thirds. Remember to tilt your hands slightly so that your fingertips are in the direction the scale is moving.
2. Arpeggios - An arpeggio is a chord that is broken up into its individual notes. Songs often use arpeggios, so warming up with arpeggios is a good idea. Practicing arpeggios will also help you play notes up and down the keyboard effectively. While scales help you play notes correctly in a consecutive order, arpeggios will help you in playing notes that skip or leap from one another.
3. Sight Reading Examples - Sight reading is reading a piece of music that you haven't seen before. Sight reading improves the student's ability to process patterns of notes, look for detail, and learn new pieces of music. Try to fit in two or more sight reading examples into every practice session. It is advisable that you pick examples in different key signatures, time signatures, and styles.
4. A Song You Have Already Learned - Playing a song that you are more familiar with is a good way to get your fingers warmed up to practice the songs that still need work. Once you learn a song, try adding in the finer details such as dynamics, articulations, and tempo. Also, try memorizing the song so that you can play it without reading the sheet music.
I use this book for a lot of my warm-ups:
Complete Scales, Chords, and Arpeggios
Most blogs written by