The thing you need to know about making a successful cookie is when to take them out of the oven. A lot of people take cookies out of the oven too early.
What people don’t know is that cookies continue to bake once out of the oven, so the trick is take the cookies out of the oven when the cookies are still soft to the touch in the middle (not sticky, because that means the cookies aren’t done all the way). Normally this time is about 1 to 2 minutes before the recipe says. You do NOT want them golden brown on the edges, this will create a crunchy cookie.
Now don’t get me wrong, sometimes cookies are better crunchy. But when you just want something soft to bite into this tip will get you soft cookies every time.
Another nice thing about a good soft cookie is that it stays better longer. Hard cookies will become stale in about 2 days where soft cookies can last about 2 days longer and in my opinion taste a whole lot better.