For most people, the most important bills are housing and transportation costs: stop paying your rent or mortgage and you're likely to be evicted or foreclosed; stop making your car payment and your vehicle will be repossessed, preventing you from, among other things, getting to work.
Make sure that these necessities are paid before you pay other bills.
Debt collectors will do their best to pressure you into paying them first, using your lack of familiarity with collection proceedings against you. Credit card collectors cannot put you in jail, nor can they take money out of your bank accounts or seize your property without suing you first and getting a judgment. Those court proceedings do not happen over night, and you will have notice of such law suits and be able to contest the claims against you.
The bottom line is: Know your rights about debt collection, and if you have questions, ask us!