If you want to play correct then you
need to tune your guitar on regular basis. This is the most basic thing which
is necessary for every guitar player. In the modern days there are many ways by
which you can tune your guitar. There are various software's available in the
market for the purpose. You can do it on your computer or on your smartphone.
If you have android based smartphone then you can try many goodies available on
the play store like gstring & datuner (there are 100s of other, you can
experiment with all of them & you can select one as per your liking). You
just need to run the software & set it to auto tune that's it, now you can
play open strings one by one, the note names will be shown on the screen live.
You need to strike the string & adjust its length until you find the
correct note.
If you don't have smartphone (as
they are expensive, android is starting from Rs. 5000 minimum) then you can buy
a separate digital tuner which will do the same thing as you did with your
smartphone. So these were the modern ways. Now think if you don't have digital
tuner or smartphone with you and you need to tune your guitar? So now i will
tell you the basic way by which you can tune your guitar (only if you tune it
regularly).