I am unsure if necroing a thread was the right thing, but I'll answer anyways.
Typically when you sell something, money is sent first, so as a seller, you should have the money in hand for both the item and shipping before you send out, regardless of trader rating.
Otherwise if you send out first it's possible they keep your item and don't give you the money.
Another option is cash on delivery so they have to pay upon the package arriving before they can open it up.
VFC HK416C Crushed Orchid - VFC SR16 BCM ZTW
TM G17 Loki Tactical Pink - TM G19 TTI Combat Master