This is a article from Meghan Nixon my number one girl for Skype vocal lessons!

Hello fellow musicians! Today I’m going to give you some advice on how to sing and play guitar
at the same time.
A lot of my private voice students play the guitar and I see them all struggle with the same
issues. I’ve got 3 tips to help you sing better while playing.

How To Sing And Play Guitar

1.) Keep your upper body upright and open. I often see my students curl over
their guitars with their backs bent towards the instrument. Beginners who are watching their
hands tend to do this the most, but even skilled players don’t always consider how their posture
affects their singing.
Your singing voice is a wind instrument. Bending the instrument limits your volume and breath
considerably. Ideally, your back will be straight & relaxed and your chest and ribs will be
open. This allows you to take the deep, low breaths you need to produce a strong sound.
Need some help with breathing?  Check out this step by step tutorial video on diaphragmatic

2.) Practice separately, then together. If you are struggling with any aspect of
playing and singing at the same time, try practicing the skills separately.
For instance, you may lose your rhythm when you focus on breathing. Or perhaps your pitch
goes out the window when you focus on playing a difficult section of a tune.
It might be as simple as singing or playing the song a few times through to work out the kinks.
Isolate whatever the weak link is, practice it separately and then put the two back together.
When a student is struggling with singing while playing, I’ll have them record themselves playing
a song and then sing along with their recording. This way they can focus solely on the vocals.
Once your singing and playing are both solid, it will be much easier to practice them together.

3.)Don’t be afraid to change the key. All singers have come across a song
that they love to sing, but it’s out of their vocal range. Most famous male singers in pop/rock/
R&B today are tenors. Most men however, are baritones. For women as well, there are a
lot of singers on the radio today who sing higher or lower than the average female range.
So, don’t strain your voice to hit notes that are out of your vocal range. Find the sweet spot
for your voice. Try a few different keys and see what sounds and feels the best. I’ll
often record myself if I’m uncertain which key sounds the best. You’ll be surprised to hear what a
difference a half step can make.  If you don’t know how to transpose, seek out songs & singers that share a similar range to
you. Do you know what your vocal range is?  If not, this article will help you figure it out Tips For Singers Vocal Range.

It feels awesome to sing with an open, well supported sound. Add in playing the guitar while you do it- even more awesome.  I hope these tips help you get more out of your singing voice. Enjoy
your practice!