Welcome to Gaia! ::

Technique wise, i'd suggest getting a book of technical exercises. If you need help on any of it, you could ask your director or someone else you know who would be able to help.

also, sit down with a tuner and work on your notes. especially the ones that you have trouble playing in tune.

if you haven't played for long, start working your way up to the higher notes now. don't worry on getting them quickly. just play them a few times everyday and once you get used to them, they'll be a lot easier to play.

tounging (heavy or light) will depend entirely on the style of the peice of music that you are playing.

make sure to support your air, from your diaphragm. a lot of people make the mistake of doing so from their throats. this can cause you to have a bright, edgy sound.

you should have a firm embouchure, not a tight one. Make sure you don't tighetn up too much when you go up to high notes, or you will be out of tune on them.

some common techniques are the trill and trimello (you'll have to forgive my spelling). This isn't even close to all of them though.

You should also make sure to learn your scales and especially your chromatic scale.

...yes actually, press the keys down hard, this will ensure that all your pads are tightly closed, which will give you the best, least airy tone possible...DON'T tongue everything "light and soft" and don't tongue staccato note hard...staccato ONLY means separated...so tongue like regular, but stop your air flow for a tiny bit then continue, so that the notes get separated. your accents and the type of music you are playing will tell you if you should tongue hard/light/not at all..don't keep your fingers RIGHT above the keys, this will force air back into the air and ruin the tone, keep your fingers high enough off the keys that it sounds good, but close enough that you can still play fast..."tight embouchure" isn't very descriptive...you could have a tight embouchure in the wrong shape and it would sound disgusting.