Cadillac Repair: vehicle is not starting, fuel test, fuel pressure

Question
I have got a full tune up on my car and replaced all parts that needed it my cadillac will not start it turns over it just seems like it is not getting enough gas to start or the spark is not sparking so it can start please help!

Answer
The first thing you have to determine is if you have adequate fuel pressure via a fuel test gage and check for ignition to the spark plugs while trying to start the car.

Once you determine which one you do NOT have Fuel or ignition, Then we can proceed.

WHAT YEAR and MODEL car ?.