i find that letting the dough rest also helps keep cookies from spreading too much.

Watch the Good Eats episode on Chocolate Chip Cookies. Alton tweaks the recipe for every taste and explains the science behind it all. One of my all time favorite eps.

I think I remember my Betty Crocker book saying something about using a cool pan for every batch, because putting the dough on a hot pan causes it to spread more before it sets.

This is shamelessly stolen from an episode of good eats called "Three Chips for Sister Marsha". Alton Brown makes a thin, puffy, and chewy cookie and explains the science between each:

Thin cookies -
*f you desire a flatter cookie, increasing the soda called for in a recipe by up to half would be appropriate.
*Since eggs tend to puff rather than spread, replacing one or all of the eggs with milk will promote spreading.
*Nothing affects a cookie's texture more than the melting characteristics of its fat. Butter has a sharp melting point meaning that, uh, just a few degrees difference between a solid and liquid states. So since conversion occurs at a relatively low temperature, the resulting batter spreads prior to setting.

Puffy Cookie
*Shortening melts at a higher temperature than butter so it remains solid longer giving the batter time to rise and set before it spreads.
*Increasing the ratio of brown to white sugar also creates a more tender cookie.
*lower protein cake flour will tie up less moisture making it available for steam production. Steam will lift the batter in the oven producing a fluffy, cake-like batter. Switching from baking powder to soda enhances fluffiness by creating an acidic batter which will set quicker and spread less.

I expect you just want the puffy version, but there's also a chewy version, he calls for using bread flour so you get more gluten and extra chewiness. he also recommends adding more egg whites to help add chewiness to the cookie.

You can check out each recipe here:
http://www.foodnetwork.com/recipes/alton-brown/the-thin-recipe/index.html
http://www.foodnetwork.com/recipes/alton-brown/the-puffy-recipe/index.html
http://www.foodnetwork.com/recipes/alton-brown/the-chewy-recipe/index.html

Chill the dough. Cool the cookies sheets. Place the dollops of dough farther apart. And buy a good quality thermometer for your oven. Your oven temps may be off.

P.S. I've never eaten a bad chocolate chip cookie :)

Let the butter come to room temperature before you mix it with the sugar. If you take the short cut and melt it, your cookies will spread out.

I'm oddly irritated by having to make drop cookies. The spacing, the merging, the 7-10 minutes to cook and then they're burnt - it all takes away from the joy of the cookie. For chocolate chip cookies, I've solved that by making blondies instead - from the Greystone bakery cookbook I got years ago. Or, if my husband starts to complain about wanting actual cookies, I negotiate that I'll make the dough if he'll do the rest. Which makes us both happy :-)

I would second chilling the dough before baking.

I always reduce the butter/oil and use a cold tray before they go in the oven (if you have to reuse trays, run cold water over the one coming out). I don't find chilling the dough necessary if I have a good, stiff texture. With some things, however (e.g. shortbread) it is very necessary.

Try a different recipe. I'm a big fan of the NY Times Best Chocolate Chip Cookie recipe. One of my friends also adores the Cooks Illustrated chocolate chip cookie which uses melted butter.

The butter should be slightly soft, not fully softened. Cooks Illustrated gives a tip for the perfect softness: you should be able to bend the stick of butter slightly without it cracking, but if it smushes in your hands, it's too soft and will spread. (If, like me, you often hurry the softening time by cutting butter into slices, just apply the same logic to the individual slice: you should be able to dimple it with your finger without pushing through or smushing it.)

Chilling the dough does help control spread, and overnight (or longer) chilling has great flavor benefits, too, as you'll probably remember from the NYT choc-chip cookie article that was making the rounds a few years back. If you don't have time to do that, you can scoop out the cookie balls and chill them quickly in the fridge; small balls of dough will chill much faster than a big bowl.

Cook's Illustrated Best Recipe Cookbook. The chewy cookie recipe.
Their "break, turn and connect" technique makes these cookies perfect.

I've made thousands of these cookies, and they've been devoured by friend and foe alike.

I usually freeze the dough in little balls, then bake later. They don't spread out that way. If you need to bake a lot of cookies, make sure the pans are cool as someone above mentioned.

Hey, thanks Emma and everyone! This gives me a lot to try. I'm actually about to spend the summer w/o my KitchenAid mixer :(, so that will give me a chance to get good at hand mixing. I appreciate all the other tips as well.

-Anna

Check the flour to butter ratio. The Nestle recipe calls for 2 1/4 cups of flour to 3/4 cup of butter. When I want thinner cookies, I decrease the flour a little. For thicker cookies, I add a little more-usually just a tablespoon or so. Also make sure the baking is fresh. But be careful. Once in awhile I decrease the flour too much and the cookies become lace-like and break easily.

And like the others have suggested, freeze the dough a bit before and place dough balls on a cooled sheet.

I'm off too to bake some chocolate chip cookies too! Have fun.

Good Eats. YES! Lookup a copy of that episode and you will be glad you did.

As for drop cookies drudgery, I use a small (about #40) disher and it works really well. SilPats or parchment are also worth the trouble.

Yeah, chill chill chill. I worked at a bakery where we froze our cookie-dough to get really thick cookies.

I always refrigerate the dough overnight, it makes a huge difference. Oh, and I had a cookbook author tell me with much gravity, "This is a GOOD cookie," upon eating my chocolate chip cookies!

If you really can't refrigerate the dough, here are other tips: if you have a stand mixer, you don't need to soften the butter first. Don't let the eggs come to room temp, chill the baking pans in the freezer, and put the dough in the fridge or freezer in between steps, if you can.

Just substitute butter flavored shortening for the butter. Use ice cream scoop to produce uniform sized cookies. Use twice the amount of nuts (walnuts preferred), toasted until lightly browned and aromatic. Works like a charm!

I played with cookie recipes a lot until I made the perfect one. Tall, chewy, not bready (as tollhouse tends to be)... perfect.

Best Chocolate Chip Cookies Ever
Ingredients
2 1/4 c all purpose flour
1 t salt (i use a little extra b/c salt + choc = yum)
1/2 t baking soda (I use Aluminum free)
1 c butter, melted
3/4 c dark brown sugar
1/4 c white sugar
2 T corn syrup
1 egg
1 egg yolk
seeds from 1 vanilla bean, or 1 t extract
few drops almond extract
1 1/2 c semisweet chocolate chips
Directions
1. Mix melted butter, egg, egg yolk, corn syrup and sugars. Add vanilla and almond extract.
2. Add salt and soda. Add flour in ~1/2 cup increments until well combined.
3. Add chocolate chips.
4. Put dough in refrigerator for at least 2 hours until firm, or overnight.
5. When dough has firmed up, preheat oven to 325F.
6. Spoon dough out onto cookie sheet while dough is cold. You want about 2 tablespoon dollops, spread about 3 inches apart. You can round them out if you like, but I just chucked them onto the pan. I lined my cookie sheet with a silpat, but I would recommend using minimal grease or spray to reduce spreading.
7. Bake for 13-15 mins, or until they look aaaaaalmost done.
8. Let cool for 5 minutes on pan, then slide off onto cooling rack. Be careful with them!
9. Try at least one while still warm and melty.
10. Yum.

Either chill the cookies once they're shaped if you're using all butter (ditto on the cool pan as well), or use butter-flavored shortening instead. Shortening has a higher melting point than butter, so it won't spread as much in the heat of your oven! My mom and I go back and forth about the best way to make cookies... she always makes hers with shortening and they are puffy and chunky. I make mine with butter and they are flat and crispy on the edges. Mmmm... now I want cookies. :)

I, too have had this problem. The answer, for me, was in how I was measuring the flour. Much to my surprise I was using too little flour. I would never have predicted that. Using a scale helps and for me, it made a tremendous difference. Now my cookies are exactly as I'd like them.

I'm willing to bet money that your butter is too warm. I use my KitchenAid mixer and cream butter almost directly out of the fridge. The bowl should feel frankly cool as the butter is creaming and you're adding the sugar and eggs.