Speak from your chest
When the voice comes out of the mouth without involving the chest it might not be that deep. Try to use your chest while talking and your voice will be deeper.
A deep voice results from loose vocal cords. Stress tightens the muscles that influence your voice and as a result it might not be that deep.
Keep your head up when you speak
When you keep your head up while you speak the voice coming out will be clearer and deeper.
Exercise your neck muscles
Weak neck muscles can force the muscles around the vocal cords to get strained easily and so it might affect the quality of voice.
Drink a lot of room temperature water
Cold water tightens the muscles and reduces the deepness of the voice. (See Why you should drink more Water?)
Learn how to increase your testosterone naturally
Exercise , loss weight and reduce stress in your life. All of those actions can increase the amount of testosterone you have and so can increase the depth of your voice. (See How does it feel like to have high levels of testosterone?)
Studies found that chronic alcohol consumers usually have their progesterone levels lowered. This can have a direct effect on the depth of the voice.
When you speak slowly you will have more control over your vocal chords and you will be able to affect each word coming out of your throat. Speaking fast might lead to a high pitched voice.
Keep your back straight
The body language positions of confidence can help you speak with a deeper voice. Keep your back straight, your both legs planted on the ground and don’t fold your arms.
Get a voice coach
Since voice can highly be manipulated getting a voice coach might help you learn how to have more control of your voice.
Speak with the back of your throat
While using your chest to speak you can also try to let the voice come from the back of your throat. This can help make your voice deeper.
Speak from your mask
Let the voice come out, in its final stage, from the area around your mouth, nose and chin. This can help make your voice deeper.
Breath from your diaphragm
Most people mistakenly breath from their chest thus reducing the deepness of their voice. Learn how to breath from your diaphragm by sleeping on your back , keeping a book on your tummy then making sure the book goes up and down as you breath.
How to have a deep voice?
How to Talk With a Deeper Voice? Is it possible to develop a deeper voice? How to have a deep voice?