when ever i try to play high notes i never get a sound out. even though i cover the holes why is that?

You just need to develop your embochure. Practice more and you`ll get there eventually.

Practise more that`ll help you get those high notes,once an expert told me to think there`s a candle right in front of you,just try to blow it out,then gradually move the candle far away(in your mind) and try to blow it out. This will help you to develop a fast, intense airstream. Also a good reed is helpful,harder reed will be able to get the high notes easier and in tune.
I also heard the Half-Hole fingering,it`s just for high C# to F#. Half covering the left hand first hole to get a easier response,but I`m not sure if that is helpful or not. But it`s just like how you learn to cross the break, in this case you are just trying to use the first keyhold rather than the register key.

The reason is becuse , like me I`m a lefty so its hard for me to cover the holes you have to make sure that your really covering the holes, and that your reed is wet enough for you to blow. And it also depends on how many years you have in playing, I`ve been playing since I was 10 and now I`m 13 and I know all the high notes already.

well what you should do is to practice slurring over the break because if you try to tounge you won`t get a sounf but a squeak so o that first.

First, yeah, make sure you`re covering the holes correct. Then. try playing those high notes you`re working on as loud as possible. This makes sure you`re using lots of air. And, air is the secret to everything. They`ll come with more practice and development, but if you want something to make a sound now, lots and lots of air.

P.S. I`m left handed, and I`ve never really had any problems with my hand not fitting the instrument correctly.

my teacher said:

1. check to see if you have covered all the correct holes, or that your not covering only half the holes...

2. blow a LOT (well, not A LOT) but more air than the chalumeau register (notes w/o register key) needs... you should get a sound.. if you don`t... just blow harder... hahah if it doesn`t work still,

3. drop your jaw a tiny bit more. i tihnk it helps... that`s what my teacher said, but iunno if i should believe him.. he only plays flute... =/

Dropping the jaw never works for me even though my teacher told me the same i never listend, do what works best for you as a player not what a teacher tells you, their not always right.

like john said, you just need to develope your embrochure.

If you are a left handed player then it will be difficult to play high notes because the fingering will be hard, but another reason may be that you are not blowing correctly. You would have to blow harder to get higher notes so just keep practising with you`re blowing techniques and you will hit those high notes.

Erm... I`m left handed.. it`s never made ANY difference to me at all? I didn`t know it should?

How would the upper register fingerings be any different or harder for a lefty?

lol, if anytihng, being a lefty helps because your dominant hand has more control over the register key... o_O the right thumb just has to sit there and support the thing...

Hand preference has little to do with clarinet playing.