Question: There's this thing that is really bothering me and so far I can't make it work. I've taken like 10 singing lessons so far and the teacher keeps telling me that when I sing notes that start to go "high" and maybe frighten me I do not push out enough air and the sound and notes stay on the back of my mouth, without getting out with the power they should. And this is not good for the throat because it feels that I kind of hold back the sound to reach the high notes.

To be clear, I'm not talking about impossibly high notes, but it seems that when I know I have to go out of a "safe range" I hold back the air. I reach the note, but not with the tone/volume/power that I had for the others.

It's hard to explain, but I do feel the sensation of what she means: is like the sound stays in the back of the throat instead of fully going out. The problem is, I can't find a way to fix this.

My teacher is trying to tell me in different ways how to overcome this, like "do not think you have to reach a high note, don't think about the pentagram, think of the notes as one after another on a line", or, from a more "physical" point of view, she told me once to "open your mouth in vertical, open up the throat", but I really can't prevent this, it's like an automatic thing that I do because I've always sung like that by myself, never knowing the right way to do it.

Does anyone have some advice that I can try, that worked for you maybe? Both mental or physical. I'm looking for something that I can use when I practice at home, when I don't have anyone to tell me if I'm doing it wrong or not.

Answer: 
Your teacher is right. There’s a great deal of technics of singing that can be reached by imagination. 

* Imagine you are standing on a higher pitch than the tone you are going to sing.
* imagine your voice is like fountain, the air is the water jet, the tone is a ping pong ball.
* imagine the tone is a thread and have to lead it through the eye of a needle.
* Imagine you are a wulf that howls at the full moon
* Imagine you are a rockstar or you are on stage singing an Aria in an opera
* always practice higher notes first by *ee, you, me, nee,* experimenting with vocals, voicing consonants.

Pictures like these and similar imaginations you can invent yourself and develop your voice and improve your singing abilities. There are no limits of experiments and discoveries. You don’t have only to develop your voice but also your phantasy.
In addition to the other answers, one physical suggestion that helped me was to **smile** when singing; a big beaming smile seems to help bring the sound forward.

(I didn't generally find that the ‘Imagine…’ or other abstract suggestions helped me much.  It was mostly a matter of learning how the various techniques *felt*, and then finding how to recreate them as needed.  But everyone's different.  And of course, two of the things that make singing so challenging are that everyone has a slightly different instrument, and no-one can really *see* it or what you're doing to it!)