-Are the pieces there just to show tehnical skill or is it advisable to throw in a few avant-gardy thought provokingish thingys(hopefuly that doesn't sound obnoxious/stereotipical)?
both, yes that's advisable (just be sure that whatever they are, they're either pieces you ACTUALLY have some kind of philosophical/symbolic relationship with to convey, or pieces that are such that you can basically just make up a "philosophy" for it that sounds believable (you would be surprised how common this is), and no that doesn't sound obnoxious
-They mentioned something about pieces being from observation and imagination.
What exactly do they mean by latter and is the latter necessary?
most likely, the following two things are the case:
"observation" most probably means things like still-lifes and whatnot, things where the art should reflect a keen eye for, literally,
observable detail which you can accurately recreate in the form of the art
"imagination" most probably means things painted without a specific real-world reference -- for example, painting a sunset on the beach from a photo or actually having a beach view, versus painting a sunset on the beach as your own mind conjures up images for when you think of the phrase "sunset on a beach" -- and which draw more from your own mind and philosophies and beliefs and views of things, rather than as those things exist in objective reality
and yes, the latter is
absolutely necessary, because being able to do art from visual reference and the like is predominantly a question of technical skill, and being able to do art from those deep places within your own mind and experiences is another matter entirely and one which is very fundamentally important to understanding many, many different artists and pieces and periods within the history of art
-Does displaying more drawing tehniques give me any extra points?
yes, but not nearly as many as you might think
understanding the "why" aspect of art is more important than understanding the "what" or "how" aspects
all aspects are important, but it takes more knowledge and intrinsic comprehension to understand the different "why" aspects throughout history than it does the different "what" or "how" aspects
-Does the fact that my high school didn't have an art class deduct any points?
i don't know your situation's exact grading system, but if i had to wager a guess, probably not
it wouldn't be fair to detract points for aspects you have no control over, after all, and doing that wouldn't give you anything to learn from since it'd be deducting values from things
other than your own knowledge or lack thereof
-Probably a no, but is there any place on teh interwebz where I could find the basics of art history or will I have to check the bookstores?
there is a place, and it's google
that sounds cliche, but considering art is inherently subjective and you have a few thousand years of material to cover and everyone who wrote about it will have a different perspective, it's simply more practical to just tell you to start with google and branch out on your own time and perspective than to give you my personal preferences
the importance of the journey of art is to find your own path along the way, and if i gave you my path and said "go here" i'd be derailing you a bit from finding your own way
but i will say, start with google, and make it a point to explore as many different sites and perspectives as you feel comfortable with, because having more unique frames of mind will give you more and more little pieces of the whole, which is really what understanding art and its history is all about
hope this all helps, even if just a little bit, as i've had to go through a lot of this in art school myself (though i wasn't going for teaching, but i did spend a year as a professor's aide so i have a tiny bit of insight into the art-teacher side of the matter) and to be perfectly frank it can be an absolute nightmare to go into blind
(it's still a nightmare, art schooling always is, but it's at least a bit less nightmarish if you have SOME level of preparation)