You don't shave up or down, you shave with the way your hair grows. just like golf, you never go against the grain. If your hair grows down and out, shave that way. Also, one of the things that really isn't talked about much is how you wipe your face off afterwords. Never wipe with a dry towel, that's the worst thing you can do. It's abrasive and will cause irritation fast. Get a soft towel, dampen (not drench, dampen) with water and again, go with the way your hair grows and dab that way outwards.
I'd also suggest something like this, to put on after shaving: http://c3.soap.com/images/products/p/be/be-090_1z.jpg
I used to have the same kind of issues in high school and all of this helped a lot. :)