Stuff you need to know
So far I've been focusing on getting you to use some very basic commands to run the Arduino. Listed below are those commands that you must know by now. If you don't or aren't sure how to use them then you must spend some time working on them. If you need more reference than the lessons on our site then you should download Getting Started with Arduino and the Arduino Programming Reference. Both of these can be found on our Electronic Bookshelf.
Here are commands that you should be able to define and know how to use:
if and if/else
Should know by now for B/C
everything above, but focus on specifics of use