There's 2 types of debtors, and only 2.
Those who cant pay for whatever genuine reason and those who wont pay.
The latter category is the worst.
If you don't get paid start asking questions which will assist you into which of the 2 categories they fall.
Cant pay, get what you can plus drip feed, pressure relatives to pay or cust to hock gear etc.
Wont pay, be pleasant, smile, appeal to their conscience if that doesn't work, be nice smile walk away ...
...Behind the scenes you go in hard, get your evidence ready, case prepared, small debts court lined up and return with the summons. You go in real hard, for the jugular, and either they pay you on the spot or you file that document and destroy their credit rating ... most of the hard core will pay at this point.
PS: I was a debt collector for 7 years.