Character- This is more on the personal information of the borrower. You need to know his or her credit history whether or not he or she has a debt in the past that was not settled.
Capital- You need to know that capital or net worth of the borrower. You can ask for his income tax return in order to see on how he or she would be able to repay you.
Capacity- You need to see one's capacity to pay. Is he has more assets than liabilities in general?
Collateral- To secure your money, you may ask for collateral or an asset that you can hold while he or she is not able to repay yet. That collateral becomes yours when he or she will no longer settle his debt to you. Make sure that the collateral is worth more than the debt he or she borrowed.
Conditions- These are the external factors (Economy, market etc.)
And don't forget about the big F.
FAKES.
Make sure all of them are real and not fake information.
People over at BTCJam were scammed with real documents they thought were true.
But I know personally about a guy who submitted bank details in full with 6 months of cc history and guess what
When they finally realized the guy scammed them, that bank didn't even exists ))).
There were hundred of cases in which people used stolen or fake ids and bought paypal/fb/tweeter account for a few bucks to prove they are real.This is why btcjam is no more.
And in the end, even if you get the real info, even if the guy passes with 5C+, what are you going to do once he is not willing to pay back?
In some countries the entire process is so hard and time consuming you'll regret doing it.