Start with a dc and new color
This is a way to start a new round on a granny square, or a new row, when starting with a dc. By doing like this you will have the tail on the top so that you on next round can crochet around it, and even if you change color on every round, there will be a minimum of tails to weave in at the end.
Put a slip knot with new color on the hook, make a yo, go through st on previous round, get yarn, make a yo and pull through 2 sts, make yet one more yo and pull through the last two sts.