The more money you have outstanding, the more negatively it impacts your credit, BUT the more consistently you pay your bills, the better your credit gets.

That gives us an opportunity to meet them and do what @John Underwood said and ask if they have any outstanding maintenance issues or concerns. 

If the interest rates were the same, paying the same total amount each month, either loan would be paid off at the exact same time.....interest charged each month is purely about the total outstanding principal, at that time.

On a general thought, start by becoming an outstanding finder of deals.

But with that 156 mail to the owner, even with an outstanding 10% return rate you will only have to filter through 15 potential sellers.

These guys are outstanding storytellers and have some of the best marketing that I have ever seen. 

If there are any outstanding loans from the federal government they will have to be paid prior to ownership.

More importantly, he is always on time, his work is outstanding, and he is just around a great guy.

A simple call to the local code enforcement agency should be able to reveal any outstanding liens and fines.

There are many hurdles that you need to get past one by one, the first of which is finding notes but more importantly pull the trigger and buy the damn thing.One recurring problem I've noticed is new investors telling me they can't find deals - but when you show them deals they don't buy anyway because they always think the notes are no good.