The best way is to give loans to those people to whom you personally know as if you give loans to those people who you do not know or those people will live far away from you then at default it will be hard for you to get that amount from them.
Yes that is the best thing to do if you are going to be a lender and you have a business like that. Only trust those people who know you personally because even you are going to ask some collateral from those people who you don't know. They will not just going to be obliged to re-pay you because you have the collateral and they are going to think it that they are going to pay you with it.
That's why if you want to success in this lending business you should take a collateral which you can easily liquidate for money otherwise don't take that collateral. If you manage it correctly, then you can make a profit on a regular basis. But don't ever give loans without any collateral.