06' Nissan Sentra Doesn't Like to Start

For a while now my Sentra has not wanted to start. It always does, but I have to turn it over and give it gas instead of it just starting up. I replaced the battery a while back, but that was not the issue. I keep up maintenance and all, so I don’t know what this might be. Any ideas?

try fuel filter there may be more than one may have an injector pump issue

I don’t think your car has a fuel filter.
Are the spark plug recent? It might help to use a throttle body cleaner to clean the idle air control air passages, the throttle bore and throttle plate.
A defective engine coolant temperature sensor can lead to a rich engine. It can be checked with a multimeter (voltage and ohm readings), instead of blindly changing it, or other parts.
A check of the fuel pressure could save you time, and money.