How to use less data on iPhone?

I have a Verizon iPhone 6 and I get 4 GB's a month and that is nothing. How can I use less? Is their a way? I wanna watch videos but I can't. Too expensive to upgrade and no home internet.

Try turning it off for certain apps. Try to use Wi-Fi wherever possible & limit data use to necessity.

I only turn my data on when I'm going to use it. I also keep my Wi-Fi turned off unless I'm using it. Doing this also saves my cell phone battery. I can go up to 8 days if I'm not using my phone a lot before I need to recharge my phone.

Use Wi-Fi

If possible, use Wi-Fi.