One thing that many say to do is to send a small amount first, and then send a larger amount after.

However, with triple entry bookkeeping, this means not only paying two transaction fees to transfer in, in means two transaction fees to transfer out.

Bitcoin networks really needs a test send feature. So, you can see if a message gets through (and not tie up the blockchain) and then send the transaction.

Because people aren't very good at seeing if a username is absolutely correct, let alone a long string of letters and number of a bitcoin address.