Cut your fresh broccoli in small to medium sized pieces, but not so small that they will be over cooked at the end of the cooking process. If you want your broccoli in larger pieces, you can also give them a quick pre-cooking treatment in the microwave to get them started (but don't cook them all the way) and then add then to the wok late on in the cooking process. You'll want to do this if you want really big broccoli pieces.
Small and medium sized broccoli pieces ready for the wok recipe