How do I get a better signal with my cell phone?

I live in Oklahoma City, Oklahoma first of all so its not like I am trying to get a signal way up in the mountains or something like that and my cell phone provider is U.S. Celluar and I have a cell phone made by Samsung with a internal antenna

I find myself having one bar most the time or no bars at all and I keep sending text messages that I don't think the other person is getting is there anything I can do to make it better