advice Getting into domain sales and need some expert advice.

Hey guys. Decided to go into domain flipping and sales. I am pretty familiar with having and finding domains but sales is a different beast.

What kind of scams should I watch out for from buyers?
Also what is the fastest way to transfer a domain with out the back and forth info swapping?
How would I verify the have received the domain?
What if its a pay-pal transaction and i receive payment, transfer and they cancel?

Any experienced sellers with advice would be much appreciated.

Thanks.