don't just roll into a skate park take base on the top of a fun box in the middle and proceed to roll around in the way of everyone.
I find the best way to get park etiquette would be roll in look around you at the whole section for a min before rolling over close to or next to the area everyone is setting of from, do a few runs from there and if you feel the need to chance your start point, just call it but be prepared to do what you call out or you look a fool.
skate parks for me is about the social aspects aswell as the riding, if your not going to chat with other riders scooter users then when they get in your way there just some scooter kid or bmx dude in your way and that makes you pissed. but if you speak to them belive it or not quite often there looking out for you and your lines because your not a nobody to them now.
its pretty much the same reason road rage is so popular, because you don't them the idiot who just cut you up.