How to fix a slow iphone 4s?

I had it for about a little more than a year. I go it last march and its so slow. The safari doesn't work sometimes bc it says too many errors occurred and the wireless network doesn't work most of the time and i have to use a speicific app like google to use the internet on my phone. I don't have alot of apps downloaded onto my phone and same with music and same with pictures. I have 300 pictures and 11 apps. And no music because i listen to pandora. Is it maybe because i have a really bad phone company? Sprint or is my phone just. Old

Is everything slow? Or just internet usage with Wi-Fi and cellular?
If everything is slow, backup everything to computer, restore to factory and then restore from computer backup.
If Wi-Fi is always slow, it may be your router and modem.
You can check Sprint's coverage map to see if you are in a 2g area and therefore have poor/slow data coverage.

May be it slow due to some new installed app or any other software, you need to check it first.