I think this is a great article but I wanted to highlight some of what I've found to be key points for making the best cookies, at least for me personally.
1. Butter should be soft, not melted. Melted butter makes flat cookies. (Some people like flat cookies -- you can melt your butter. Heathens.)
2. Follow order of operations in the recipe. Butter is creamed with the sugar, then add wet ingredients, then add dry ingredients. Stir after each stage. Batter should be extremely smooth.
3. Ideally, batter should be chilled in refrigerator before using. But this is not required, unless you melted your butter.
4. Once formed, roll cookie dough balls in sugar before putting them on the parchment paper. Adds slightly crunchy, brown outer layer.
5. Sprinkle some coarse salt on top, to taste.
6. Use multiple types of chocolate chips. Specifically, I like a mixture of milk chips + semisweet chips. This makes the cookie flavor less boring.
edit: In terms of the base recipe, I use the Joy of Cooking recipe. Tollhouse chocolate chips also have a recipe on the packaging which is basically much the same.