If you're just joining us, I'm going through the entire process of making macarons and considering the different approaches and what's worked best for me.
1. Ingredients and Prep
To review, the shell's main ingredients are almond, egg white, confectioner's sugar, and granulated sugar.

The almond portion of the shell must come from almond flour or meal. (I've found the Bob's Red Mill brand at Whole Foods and other stores in New York, or you can order it here.) It's important for the texture of the final product that the flour be as fine as possible, so you should put it with half the powdered sugar in a food processor to fracture the larger grains; the sugar keeps it dry and prevents it from becoming almond butter. If you don't plan to use almond flour for a while, refrigerate or freeze it.
The next step is to filter out the large grains that remain by putting the almond flour through a tamis, a flat fine mesh sieve. I've been getting by with a mesh strainer and a spoon, but this is one of the most arduous and time consuming steps in the recipe, so any tool that makes it easier may be a worthwhile investment. Lastly, mix the almond flour with the rest of the confec. sugar and you've got tant pour tant!
The egg whites are a fun little world all their own. There is general agreement that older egg whites have a thicker consistency that is better suited to making foams. Some simply recommend using egg whites you bought a week or two before, while others talk about leaving the whites out, uncovered, for anywhere from an hour to three days to let some of their water evaporate. (Supposedly they have their own bacteria-fighting agents; your disgust may vary.) I haven't found all this to be strictly necessary, but I do use older whites when I have them, and let them sit for a little while when I don't.
There's also been talk of using powdered egg whites to help stabilize the foam. I finally found some, the "Just Whites" brand, at an Upper West Side health food store, the kind that sells a lot of other foods and nutrients in appetizing powder form. I've been sprinkling in a pinch of them, but again, I wouldn't go out of your way for it unless you're stuck for ideas, or obsessed like me. Cream of Tartar can also perform this function.
The sugars, thank goodness, are just sugar.
2. Putting it Together

So you've got your tant pour tant and your aged egg whites. If you're going with meringue Italian style, proceed by putting your granulated sugar in a saucepan with just enough water to wet it thoroughly. You will heat the sugar up to about 114 Celsius, and while it is heating use your mixer to whip the whites to stiff peaks. The former task requires a candy thermometer and careful observation so that the sugar doesn't burn or become caramel. Once it's hot enough, slowly drizzle it onto the egg whites while you continue whipping. Make sure it doesn't all sink to the bottom, and the meringue should become extra glossy. Don't worry too much about overbeating, as you want the mixture to become stiff enough that you can turn the bowl over and see essentially no movement. It's as I'm finishing this step that I like to add coloring.
Note: this was where the PH10 and Syrup and Tang recipes went horribly wrong for me. With half the egg whites left out of the meringue, there was not enough to absorb the sugar, and I ended up with something bearing a striking resemblance to marshmallow fluff. In fact that's what it may have been!
If you've got a nice meringue, the time has come to mix it with the TPT and finish the batter. I found this to be a nerve racking moment, as it determines whether the texture will be right, yet any damage has probably been done--there is a limited amount of magic one can wield with the right folding technique. Everyone says the batter should "flow like magma," but for some reason it took me a long time to figure out that this meant very, very slowly. It should look like it's stationary at a glance, but settle a little bit over the course of 30 seconds or so. It's also commonly said that you should not worry about the meringue falling, because it is supposed to fall. I think the reality is a fascinating mixture of a gooey batter and the foamy meringue, and that's what makes these cookies unique. In any case, you want to mix the ingredients thoroughly but not more than necessary.
3. Piping your way to madness
These cookies have to be piped onto the baking sheets. I've found two tools to be indispensable for this:
- Target templates made in your favorite application with 1.5" diameter circles spaced 1.25" apart, on 8.5x14 paper. You'll put these underneath your liner (I use Silpat, others parchment paper).
- Ziploc sandwich bags. If you're proficient with a pastry bag, more power to you, but the batter is quite sticky and I really appreciate knowing it's not going to leak out the other end (that sounded dirty).

Prepare your baking sheets with the templates and distribute the batter into the bags. I prefer to stretch each bag over a glass when doing this. When you are ready, cut a 1/4" to 1/2" diagonal off the corner of one of the bags. To pipe, position the bag vertically about an inch over one of the targets. It will take considerable practice to get the right size and shape. The best you can hope for until you become a zen master is that all the irregularly shaped ones have decent matches. If your batter is stiff enough the batter may not spread to make a smooth top. In this case, dip a finger in water and carefully pat down the peak.
If you are decorating the shells, this is the time to do it. For my mogador recreation I used cocoa powder and a makeshift sprinkling device.
Once piped, the cookies must sit out for anywhere from 30 to 60 minutes before baking, depending on the consistency of the batter. When ready the tops of the shells should appear dry and you should be able to touch them (carefully!) without any batter sticking to your finger. A fan can speed the drying process.
4. Baking your way
There are a LOT of variations here and I tended to constantly adjust my strategy batch by batch, but I'll try to cover as many ideas as I can.
Oven type: some prefer convection, others don't. You're probably just going to use whatever you have anyway.
Shelf placement: originally I used The Sweet Life's idea of putting one oven shelf on top and one near the bottom, and rotating baking sheets between them after half their baking time. Lately I just put one shelf in the middle so I can give each batch my full attention.
Temperature: 325 to 375 F. Some say to use 375 for the first half of baking, then lower it to 325. Others keep it constant. Some allow the temperature to fall by propping the oven door slightly ajar during baking, also mimicking convection with the airflow.
Time: anywhere from 15 to 20 minutes depending on the consistency of the shells.
What to look for: The cookies should rise and get their 'feet' after the first six minutes or so. After that you're waiting for them to bake enough to easily come off the baking sheet without getting too browned on the top. If this proves difficult it's probably because your batter was too fluid or your meringue not stiff enough.
Removal from the baking sheet: People have suggested all kinds of methods for this, from lifting up the lining and running water onto the hot baking sheet to steam them off, to placing them in the freezer for a minute, to voodoo-esque rituals. I've pretty much found, at least with Silpat, that they're either ready to come off and it's easy, or they're not and it's impossible and you disembowel them, as seen below. You can sometimes salvage things by putting them back in the oven for a minute or two.

Where did I go wrong? If your shells cracked in the oven, it may mean they didn't dry long enough. If the tops wrinkled or are very thin and fragile, it's probably a consistency or mixing issue. If the feet are absent or deflated, it's yes, consistency. If the shell rose unevenly or had an aneurysm and exploded out of the top, it's because during piping the batter got 'stuck' to the sheet at one or more points around the edge. You can learn to spot this and free it with a knife before baking. The air pocket that develops in the middle of the shells is something I don't see in Pierre Hermé's cookies. But I haven't been able to get rid of it, and it isn't a huge problem as long as the tops are strong enough.

If you've made it this far, congratulations, you're insane! Next time I'll talk about fillings of both the cookie and dental variety, seeing as how one leads to the other and all.