Each note you play has its own basic pitch tendency. Some of these are pretty universal, e.g. C# in the staff is often sharp, D above the staff is often flat, and some of these are unique to your own playing, e.g. my low C tends to be really sharp! If you want to improve your intonation, it’s helpful to know what those basic tendencies are so you can anticipate necessary adjustments and avoid playing notes out of tune. Following is a basic exercise for using a tuner to find out what those tendencies are and get you on your way to improving your overall intonation.
First, make a chart listing every note that you practice every day, probably from C or B below the staff up to C or D two octaves above the staff, including flats/sharps. If you keep a practice journal, you can include the chart as part of that. Graph paper works well for this or you can create a chart on your computer with a program like Excel.
Then pick a note to start on! I recommend starting with a note that is comfortable and reliable so you have something consistent to refer to. Wherever you start, always play with your best tone. Remember, everything is a tone exercise, so don’t practice with a tone that’s not so great! Also remember, good intonation is a component of good tone; when you play in tune your tone sounds better and some of the skills you need to produce a great tone are also skills you use to play in tune.
Now play that first note. Play it using your best tone and without looking at the tuner. When you feel you are playing the note as well as you can, then check the tuner and see where the note is registering, whether it is flat or sharp or right on the button. On your chart, notate what the tuner indicates. You can enter in the number of Hertz that the note was high or low, you can use + or – signs, up or down arrows, or even just “sharp”, “flat”, etc. Just keep it easy to read so you can make sense of it later.
It is of the utmost importance that you play the note first and then check the pitch! If you are mainly concentrating on chasing the needle or the little lights on your tuner’s display you will never achieve the quality of tone and intonation that you want. Start with a solid, well-centered tone and then adjust as needed.
After you have gotten the first note measured, work your way through all the notes, notating their flatness and sharpness on your chart. Over the course of a few days of doing this, you should be able to determine the general pitch tendencies of each note. After a few more days, you may even notice those tendencies changing a little bit, hopefully evening out and being more in tune with the tuner.
This exercise won’t completely fix your intonation problems, but it is a good first step. The goal is to increase your knowledge of your pitch tendencies and increase your awareness of how your tone and intonation are being produced so you can adjust them at will. Eventually you will learn how to use a tuner more effectively so it can be a tool facilitating change rather than simply being an instrument of measurement. Ultimately you want to free yourself from the tyranny of the tuner display and be capable of playing with good intonation in any situation, sans tuner, but more on that later. So make your chart, get out your tuner, and get practicing!