Don't fly aggressively and don't install FPV or a gimbal. The additional weight kills your flying time. If you keep the phantom completely stock and don't add anything to it, you'll probably fly for about 10-12 minutes.
I thought he wanted to ask how to keep the battery in shape for the longest time.
If so, do not fly until the capacity of the pack is less than 20% and you can use the gadget below to check the pack.
The stock charger works fine and you can set it at 3A, which will give you max 1.8 amp anyway.
If you use the high power charger, keep the charge rate at 1C even though the pack may claim much higher charge rate.
If you are in a hurry you can try more than 1C but keep your eyes on the pack and check the temperature too.
It should be just lukewarm at most.