My double crochet blanket edging is uneven and i cant figure out why?

I am new to crocheting so im sure its an easy fix however i cant seem to make my edging even. Im doing a double crochet pattern very simple. But im seeing so many different ways to do it on the web. So at the end of a row i add three loops and then go through the second stitch then at the other end i go through the extra loops i added on. Well thats what im doing any help would be great thanks