I bought a 1991 honda accord ex... we replaced the starter, spark plugs and now the battery... however when we try to start the car sometimes it doesn't want to turn over the first sometimes second time... you have to gas the car while starting it... where do I start in trying to fix this problem?

Test/replace the Engine Coolant Temperature (ECT) Sensor, which affects fuel injector pulse width. It's located on the thermostat. The ECT Sensor is a temperature dependent resistor (thermistor), whose resistance decreases as the engine coolant temperature increases. It provides a richer mixture when cold, leaner mixture when hot. It's located under the distributor and has two wires going to it.

Thank you I will try that first... I'm also going to add a little bit more info to my question.. please let me know if you think it could be anything else...

Okay so when we first bought the car ran fine I drove it about an hour and a half home.. 2 months after the car wouldn't start only click... sometimes it would take 5 or 6 tryes to get it going. Meanwhile it would still do this thing.. anyway we fixed the starter not the problem.. dug around some more till we found the ignition switch.. that fixed that problem... so now 3 months later the car would do this same starting problem... in the morning(rare) or after driving the car... you try to start the car.. if you don't gas it enough to get it started the whole car would die and would have to be jumped.. chnaged the battery.. now 3 days later when I start me car in the morning (still rare) or after I drive it (most common) the car sounds kind of like when its out of gas and don't want to turn over.. so if while turning the key gas it at the same time it fires up.. sounds like ****!! So for the first min or so the car rund rough like it will die but after you out the car in 1st or reverse it runs fine..,. oh the car is 5 speed... never dies out other than my poor release of the cluth.. sorry to keep this going forever but I'm a single mom that wants to make sure I get it done right the first time... :)

If the spark plugs have not been changed in the last three years, I would install new plugs (NGK only). I would also replace the Ignition Control Module (ICM) and coil:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-4.html#post265896

ICMs and coils are very problematic on older Hondas. They are responsible for the engine suddenly dying on the road, difficult starting (especially after the engine is hot), fluctuating idle rpm, and a lack of power when accelerating, among other things. To keep the cost down, buy the parts online or at your local auto parts store. Be sure to apply the heat transfer compound to the back of the ICM.

Jumping modern-day cars is dangerous. There's a fairly high risk of a voltage spike being able to fry the ECM (computer), alternator, and sensors. It's best to remove the battery and place it on a charger. Most auto parts stores will test and charge batteries for free.