I recently replaced wax ring on toilet. Followed directions on box. It still leaks. Any tricks to assure a good seal first time?

You would not be the first person to mess up a ring install. Let's start with a question or two. How does the height of the flange compare to the floor level, are they the same?

Let's start with a more basic question. Why did you replace it the first time? Not something you normally have to do unless there is some other problem.