Your baking chemicals might be old. If you've had your baking soda since disco roller skating was en vogue, it's time to toss it and get another box. When you buy your baking chemicals (and ground spices), write in big bold letters THE DATE they were purchased. TOSS them after one year. It's heart breaking to whip together a batch of your favorite (something) and have it go wrong because of such an inexpensive item. One other possibility - did you omit the baking chemicals altogether? (It happens to the best of us...LOL.) All-butter recipes can cause flat cookies. Butter + Shortening tend to make a puffier, crispier cooky. Once you are sure your baking chemicals are fresh, try refrigerating the dough before baking. I have found it helpful to form the cookies, chill them, then bake them. I make huge cookies, using 4 oz. of dough ("monster cookies") and these definitely benefit from chilling after I form the patties. If your dough is downright warm when you start baking, you're nearly guaranteed flat cookies. Chill the dough in logs while you clean up the utensils you used to mix it and prepare the area where you'll cool the cookies. (A 30 minute chill is customary.) If you use hot baking sheets (from prior batches), this will also cause flat cookies. Cooky sheets should be cool when you load the cookies onto them. Good luck!