This site might be a good reference in case you do not have a dictionary that explains the stroke order:
漢字の正しい書き順(筆順) - 「書」の書き方
Also, please remember that stroke order may differ in standard script (similar to what's being used as basic PC font) and cursive scripts. So, mastering the standard script stroke order is the first step.
Also, some basic information is to be found here:
Stroke order - Wikipedia, the free encyclopedia