iDzBowl, what brand paints are you using? that can make a lot of difference in which colors you need to blend to get the desired color you're looking for.
as for your questions:
when i'm mixing colors, i use either a small palette (if i'm mixing a small amount) or an empty paint jar (for a large amount if i am covering a large area or a LOT of figures: like for an army).
to lighten a color, typically, use white. mix in VERY small amount of white to the color you want to lighten. just keep adding and mixing in small increments, until the color is bright enough. (you can also do the reverse and add a small amount of color to some white paint. this will get you a VERY bright/pale color).
to darken a color: you can use a similar approach except with black instead of white.
for mixing two colors: the EASIEST way to figure this out is to pick up a "pocket color wheel". those bad boys are invaluable!
GrapeSoda: i'm not procrastinating....i'm just lazy. oh...wait....