How to pedal more efficiently on my road bike?

I have it on the highest gear and it still seems like when I get up to pedaling that I'm going too fast. Like, I'm not going too fast for me, I just mean I end up pedaling so hard that my legs can't keep up. I can't seem to just pedal normally and fluidly. And when I see other bikers they seem to be keeping a rhythm and they're not pedaling so quickly their legs will fall off. Hope this makes sense!