1997 Chevy Blazer Car wont start. Just replaced Fuel Pump

1997 Chevy Blazer 6 cyl Two Wheel Drive Automatic

Please help me. A mechanic came to the house and diagnosed that fuel pump was bad, to save some $$$ I replaced myself, car started right away, test drove it, etc. Next day the car died and wont start. What can I do or check? I called the mechanic but he want $$$ every time he does a diagnose, and im short of $$$. After reading some posts it seems that I need to check the gas pressure first then go from there. I'm planning to change the gas filter (might help), also need to check the relay and pressure regulator. I'm a newbie, any advise will be aprecciated, Thank you.