You have a lovely voice, first off, and when I have more time I want to to listen to this a few more times and expand on what I will say now.

The first thing to work on is breathing. Breathing, breathing, breathing. What I've always done is focused on keeping about 20% of my lungs full of air at all times. You have to get in the mind set of breathing before you physically need the air, or you end up gasping. Also on breath, breathe using your diaphragm - you sometimes are taking quick, harsh breaths and it's very noticeable in your chest as your shoulder rise each time. Practice breathing deeply in and out using your lower stomach - proper, supported breathing will expand your stomach, sides and even your lower back a bit (well, you can feel it there, anyway).

Vibrato - Vibrato is beautiful, especially natural vibrato, but it can get out of hand very quickly (this can also be attributed to nervousness/shakiness and lack of full, supported breathing). You might want to work on evening out the vibrato just a bit, because it can bend your pitch and make a note waver between in tune and not.

You have a nice strong voice - don't be afraid of it! When singing a solo piece, err on the side of strong pitch and tone rather than breathing for softer moments. I don't know if you have sheet music, a score, or if you learned this by ear, but anytime you see a piano in a solo piece, you make it relative to what you can sing. Soft is only as soft as you personally can sing while maintaining proper breath control/support.

On that note, your breath should be hitting your soft palate to produce sound, not coming from the back of your throat. Think of your air as a hose - lower notes should make that hose hit behind your teeth and in your mask (cheek area, behind upper lip), the higher you go, the higher the hose will go, directing your air in a stream against your soft palate. This will make singing louder and more confident so much easier, and it stops you from hurting your throat with tension. Your breath seems to be almost sighing out at times, watch yourself and note when you hear that happen - because it brings down your pitch with it.

Relax a little! You carry some tension on your upper body, throat and jaw. All of this comes when a person is nervous or unsure, and as a performer it takes a lot of practice and focus to force yourself to relax. Take stock every so often and think to yourself "Am I clenching my jaw right now? Are my shoulders really tight?"

Open up! This goes along with forcing yourself to relax, and this is also the bane of my existence some times! Your keeping all of the words very inside your mouth and throat. You need to open your mouth more and really enunciation everything with your lips. You might feel silly at first, but you will be amazed by the improvement just this can make!

Don't be afraid of your head voice, either! So many music theater folk think everything has to be chest voice, but it's simply not so! I do think you can hit those higher notes with more support and confidence if you work on them, but it may be more comfortable for you to practice going between your chest and falsetto!

You do have a lovely, lovely instrument. A lot of raw talent that I think you could really refine well with practice!

Oh goodness... well, I don't think I will need to expand much more unless you want me to clarify any of this, haha.I get a little passionate about this sort of thing =) For the record, I am a 20/female/vocal performance major at a private university who has been taking lessons for a number years. I don't know it all, but I know enough, I think, to be helpful!

Holy crap this kind of turned into an essay... sorry if this is way more or totally different than what you were looking for!