In school band we're doing a piece that is largely 6/8 time, with a bunch of 9/8 thrown in there. Another piece is basically all 12/8. This is my first experience with these time frames and I was just wondering if anyone could offer some advice for me to better count these time frames. This is how I understand is the way to count them:

6/8 = 1-2-3-4-5-6
9/8 = 1-2-3-4-5-6-7-8-9
12/8 = 1-2-3-4-5-6-7-8-9-10-11-12  

Isn't there an easier way to count this than that? Does 9/8 convert into basically 3/4? and 12/8 into 4/4? I don't understand this at all...  if 9/8 does convert into 3/4 then do I have to play practically double the tempo that the conduncter's conducting?

Any help?

Since these meters are all 'something over eight', the pulse stays the same throughout.  I always found it helpful to count aloud while sorting things out.  The first link in Bart's post above uses bold-face to highlight the numbers that make the pulse, when you count aloud, accent those numbers a bit with your voice.  

1  2  3  4  5  6

1  2  3  4  5  6  7  8  9

1  2  3  4  5  6  7  8  9  10  11  12

You'll feel it.

9/8 is a compound triple meter. You can think of it in 3/4 if each group of three eighths are thought of as triplets. Notation wise it's very different, but you could write something in 3/4 and 9/8 and it would sound exactly the same. This is how compound meters where created. Their sole purpose, in the beginning, was to give the composer a way to notate without having to write triplets.

Look ...
The quarter note gets the beat or pulse in 3/4. With 9/8, even though the eighth-note get's the beat ... we'll allow the pulse to be the dotted-quarter. Doing this, you could play each measure back to back and they would sound exactly the same. The only thing that has to happen is you go from the quarter-note being the pulse to the dotted-quarter-note being the pulse.

6/8 is compound duple meter. It's normally felt in two, despite the fact that the eighth-note gets the beat. You could write two groups of eighth-note triplets in 2/4, and it would sound like 6/8 ... as long as you do what we did earlier ... change from the quarter-note pulse to dotted-quarter-note pulse. However, look at this next notation:


Here you can see how even 3/4 can sound like 6/8. In this case, you don't not need to change the pulse; both have the quarter-note as their pulse.

Wow, Bart that actually helped me out even though I didn't think I needed it.    Thanks for that little lesson there, I'm definitely going to look more into the theory behind these time signatures.