Paypal, or direct bank transfer. However, if you're dealing locally, cash in hand is best
Ship via a reputable, fully insured(unless you like tempting fate) carrier. Fedex, DHL, USPS, UPS, etc.
Keep your buyer informed about shipping, shipping details, etc.
Over-describe things. I've always found it better to over-describe than try and "hide" something and hope they don't see it.
-Dan