Metronomes and tuners are essential practice tools. Using a metronome will allow you to practice your music with a steady tempo. Be sure to practice music slowly before you gradually increase the speed. Using a tuner will allow you to see if you are playing a note sharp, flat, or in tune. Below are some recommendations for both metronomes and tuners.

Metronome and Tuner Apps
Tonal Energy
Metronome Plus
Tempo

Metronome/Tuners for purchase
Korg TM-40 Metronome and Tuner

Online Sources
Online Metronome