Read about the collaterals in the stickies. The only way to stay on top of a borrower is by securing a collateral of value from the borrower. Of course for people whom you know and trust you can try doing non-collateral loans. Still its always safer to accept a collateral to give a loan.
Keep in mind no one will send you collateral directly, as you could simply disappear before sending the loan.
If you have no trade history, you need to use an escrow, which adds to the fees. :/