It’s not something that can be learned. You have to just start with an extremely easy piece, sightread, and get harder and harder music.

i think it is helpful in some way

I just recently took a music theory class myself. The only singing we did were notes, scales, etc. For example, you’ll start out on a tonic note and you’ll have to sing up or down to the note you’re trying to determine. It’s fairly easy. You don’t have to be a great singer to sing notes and it depends on the teacher/professor whether or not you’ll be singing in front of the class. Don’t sweat it though! I thought it was an easy class aside from some theory exercises. You’ll learn what you need to learn in order to sight read music and sing notes.

Usually in an exam situation, the examiner allows you to stare at the music only or try it for 30 seconds before he/she starts to evaluate you from the beginning.
I usually stare at the music for 10 seconds or so before beginning, this is what I usually look for:
-the key (look at cadences)
-dynamic changes
-perhaps the composer
-articulation
This is my recommendation:
Get music that must be UNFAMILIAR to you that are around 2-3 levels below your current level, observe the dynamic changes and the number of sharps/flats. Then SLOWLY play through the piece. Speed means nothing if you are making a million mistakes.
This will help you to improve your sight reading skills SLOWLY .
Most people don’t just go “Oh today I’m going to work on my sight-reading.” The more pieces you learn, the better your sight reading skills, this is why some people as you call it, “can sit down to an unknown piece and play it from the beginning to end without having to stop.”And never, never, try to memorize pieces so you don’t have to read them, not if you want to improve your sight reading.

well i wasnt saying it wasnt helpfull to EVERYONE, just that it didnt help me much. I dont see why that would get me a negative on the comment ;-;

You are definitely going to have to learn western music notation. It will help you out a TON. I trust you to have good ears, and I think it is great that you learn your pieces by ear! In fact, I think that people should start out learning by ear and then move to theory. But, having a solid theory education will be unbelievably helpful in many ways. For example – lets say you sit down at the piano and pump out a really awesome melody. Where do you go from there? Well, harmonically, you could try a half step modulation. If that doesn’t sound good to you, try out a common chord modulation into a relative key. Bingo! Say that works for you, but you want to develop the melody a bit further. What do you do? Well, maybe you can jump from the root to the perfect fifth, rather than the major third. Or, you could change the major third to the minor third, add an augmented fourth, and make the melody sound really blues-y. Do you see what I mean? Having a good theory background will help you decide what will sound good based on fact. Based on science. The spirit and emotion of the music then is all up to you. You provide the heart and the soul. You know that Indiana Jones Theme Song that is so catchy? John Williams, the master of movie composition, wrote that melody to be powerful and strong. So, when he harmonized it, he used a major seventh chord for each note. That is 1 3 5 7 (CEGB). If he flatted the seventh of the chords, and flatted the seventh of the melody, it would sound totally different. Add a ride cymbal, and that would be some seriously jazzy crap! What that is is a dominant seventh chord. 1 3 5 flat 7 (CEGBb). That is actually the most common chord in jazz. The point is, though, knowing this stuff will allow you to set the mood when you know what you want the mood to be. Classical theory will be a huge arsenal for you. And believe me – it is not actually that hard! If you are willing and motivated, you will pick this up in no time at all.

You need a teacher. That is a must. College is a definite possibility, but if you do not want to go to college, that is absolutely fine! But then get a private tutor. Find someone who will help you step by step at your own pace understand everything.

But, the most important advice I can give you is to find time to sit down at the piano or guitar for an hour or two at a time and compose. Whether you write it down is up to you – I never write down what I compose, I remember it all. But just play! Even if you don’t think you know what you are doing – just play random crap and eventually you will suprise yourself. Trust me. It is the most rewarding experience in the world. You will come up with some awesome stuff that is totally your own. And then, after you learn some theory, you will be able to orchestrate it however you want.

Composing is a blast, pal, and don’t ever give up. Don’t take any crap from anybody – you are on the right track, and if you are motivated, you will write some great stuff!

Really, there’s not much you can do besides practicing. Theory helps a lot, as does familiarity with the keys. Also, try to be thinking at least a measure ahead of what you’re actually playing. Otherwise, you won’t have time to process.

Yes the notation is the same but guitar is played an octave higher . It also usually just uses the treble clef and ledger lines added above & below as needed.

I play jazz music too and what I’ve learned over the past four years that I’ve been playing is that if you start with the band and end with the band you will be okay. I’m not saying to fake it and not learn how to actually read but if your like me, the basics really help. If you have a good ear for music, then you should be okay improvising. If you don’t, I suggest you learn how to read. Also, ask your band director what he/she wants.

Confused. Jazz is all about improvisation. You could write it down but for every 10 times you played some thing you’d play it differently. You’d be sight reading a dictionary. There’s a bigger trend to playing by ear these days.