I started an email about this some time ago, thinking it would behoove us all to have some common agreement on principles of building drinks so we might attain a level of consistency in teaching these classes/seminars.  So I'll start it as a thread & we can all add thoughts/personal techniques/criticisms.  I know the initial argument against this sort of discussion was the threat to deprive us all of individual style.  That's why I'm talking less about things that I like to do behind the bar, more about those things somewhat universally argued to be the fundamentals.

1.  Build dry: I find this an essential technique behind the bar, & for some very pragmatic reasons.  First, I'm dilution-ratio obsessed (& I'm gonna copyright that phrase, since I'm certain it's the first time it's ever been used).  The easiest way to control the level of water achieved in stirring/shaking is to know exactly when that process starts.  But more simply, the second I add lemon/gin/cointreau to that Corpse Reviver #2, I realize the damn Lillet never got stocked.  So as I'm running to the back to grab the bottle, the rest of the drink isn't sitting on ice becoming a horrible puddle. The exception here, is martini/manhattan, choosing to incorporate what ice melts by introduction of liquor into the ratio.

2. 6-second shake: again, dilution-ratio obsessed (copyright Daniel Shoemaker 2008). 

3. Shake vigorously: to quote Savoy (from memory, don't hold me to exact phrasing), "You're trying to wake up [the liquor], not put it to sleep."

4. Stir any cocktail comprised of only liquor.  I know there are many who would argue this is impossible when busy, & this is a fair argument for the praxis.  But the discussion of what corners to cut & when is for another post.

5.  Shake egg white cocktails dry first, then w/ ice.  Egg whites don't like cold or water, so getting them to froth nicely first by a 20-30 second shake w/o ice is critical to that ever-so-lovely layer of deliciousness on top.  I've had some bakers tell me eggs love copper, so if anyone comes across a copper shaker, let me know.  A buddy of mine in SF says he uses a copper coil during the dry shake process, as a sort of whisk.  Haven't had the chance to try it out yet.

6. Don't use same ice twice to mix.

7. Don't mix more than 1 cocktail in same shaker at one time.

8. Fresh juice: should be #1, but too late.

9. Zest citrus over cocktail, discarding peel.

10.  Jigger.  I'm certain many will clamor over how unnecessary these stainless steel beasts are.  But I can only say that we're most of us reaching a point in the evolution of the cocktail where precision & balance is everything.

These, anyway, make up my top ten. 

#1, I've also had it told to build by expense of ingredient, so that if the drink is "ruined", the loss is kept to a minimum.

#2, I generally shake until condensation starts to develop, to adapt to varying levels of ice.  I've got one 8 oz. scoop, but my precision with it isn't great.  As well, seeing as my ice size can vary, and whole or crushed (the delight of the home bartender is being as lazy as you want to).  I've often considered developing a shaker that measures and notifies temperature (and provides more surface area for ice, etc.) , but it's a pipe dream for the time being.  The 6-second shake sounds good for a consistent level of ice, but I'm wondering what amount of liquid (3 oz. cocktail vs. a 6 oz. cocktail) would vary the temperature.... hooray for other people obsessing over minutiae as well if not better than I do!

#3, I think the most poetic way this was ever put was in the Thin Man, "The important thing is the rhythm! Always have rhythm in your shaking. Now a Manhattan you shake to fox-trot time, a Bronx to two-step time, a dry martini you always shake to waltz time."

#4, I stir generally for appearances sake.  In my experience, the shake froths the drink, and the stir keeps the surface clear as glass, and the shake seems to keep the temperature down for a bit longer.  I've also heard it told to shake if the drink involves brown liquor/fruit juice, and stir if white liquors... though, I'd still like to have a drink presented with the Gin "bruised", just to see what is meant.

#5, yes, yes, a thousand times yes.  I'm excited about the copper concept as well, though I'd like to see comparative results.  If I had one wish, amongst many others, it would be to go out to breakfast and get a right proper Ramos Gin Fizz.  Though a 12 minute shake can be a bit much to expect... though maybe this item could help (HA!)

#6 and 7, damn straight.  It's just telling your guest that the drink was made just for them, with no corners cut.  It's just being properly hospitable.

#8, fresh squeezed each morning!

#9, I'm getting rid of a small garnish diatribe I could go into.  I concur with the need to express the oil, certainly.

#10 This hits upon something I look for in a bar/bartender, which is consistency.  Again, a diatribe regarding speed pouring vs. the use of proper measure (the varying weight of the bottle through its lifespan, liquid viscosity, etc.).

I suppose I could've just responded with a "yes"?

Perhaps we should split this thread into professional techniques and home techniques. I'm not trying to hurt anyones feelings, but what I do professionally sometimes is much different that what I'm willing or able to do at home. At the bar, if someone orders 4 purple hooters from me (and no, I've never made a purple hooter at Meriwethers, but occasionally I do get a kamikaze), sorry but all four of those babies are going in the tin together. Call me a snob but I wouldn't do that with a call for 4 martini's (well, maybe if they were dirty goose martys I just might).

From the Savoy Cocktail Book:

A FEW HINTS FOR THE YOUNG MIXER

1.  Ice is nearly always an absolute essential for any Cocktail.
2.  Never use the same ice twice.
3.  Remember that the ingredients mix better in a shaker rather larger than is necessary to contain them.
4.  Shake the shaker hard as you can : don't just rock it : you are trying to wake it up, not send it to sleep!
5.  If possible, ice your glasses before using them.
6.  Drink your Cocktail as soon as possible.  Harry Craddock was once asked what was the best way to drink a Cocktail : "Quickly," replied that great man, "while it is laughing at you!"

re: Daniel's comments

1) Yep, you never know when you're going to have to run down to the basement because you've forgotten to unhook your camera from your computer.

2) Seems reasonable, depending on ice.

3) Oh, yes...

4) Generally, anything with vermouth I'll stir, unless it has eggs or cream in it.  When it comes to fruit juice, unless it is a significant percentage of the drink, I'll still stir.  And anything with herbs in it should be rolled, not shaken, or you break the herbs apart too much and it tastes like plant guts.  In addition, big, square ice for shaken drinks and freshly cracked ice for stirred drinks.

5) At Alembic, when they make their pisco sours they use a stainless coil from a bar strainer in the dry shake portion.  Some of the bartenders do get a really good head on their egg whites.  But, when I was talking to Colliau and Adkins at Slanted Door, they said they'd tried shaking with and without the spring and found no real difference.

6) Yep.

7) Well, no more than 2, unless you have a really big shaker.

8) Yep.  Though, I have to admit being sometimes fond of dropping it in, or using the long zest garnish tied in a knot.

9) What other kind of juice is there?  Obviously, within reason.  Fresh passion fruit juice or even pineapple are a bit tough.

10) I always measure, because the drinks are better when I do.

I agree, this is a good discussion.

My thoughts on Daniel's suggestions-

1) no argument.

2) Being dilution obsessed, I think 6 seconds really puts one in a bind. Are you considering factors like the size of the cube, ambient temperature, temperature of the ingredients, temperature of the ice, relative humidity and purity of the ice? I would think that any or all of the above factors could affect the dilution rate to the point where a 6 second standard seems difficult to use as a rule of thumb.

3) Amen. Shake the hell out of that thing. Two things I hate in life, limp handshakes and half assed shaking.

4) For me, I do this every time at home. However, our standard at the restaurant is that martinis are shaken. Right now, I shake 100% of the vodka martinis just for expediency and (against house policy) I stir gin martinis almost all of the time (98%). I personally don't think stirring a vodka martini makes any difference, its still a piece of shit, but I do think it helps gin properly blossom in the glass.

5) Until we experiment with a copper shaker, I'm staying out of this one.

6) I find used ice to be perfect for lots of cocktails. The ice is already flavored and the dilution rate will be increased because the ice is already warm. :) I'm kidding.

7) Sorry, can't agree on that one.

8) When possible I agree. But fresh squeezed cranberry is atrocious

9) over the drink yes, but I kind of like the garnish in my drink.

10) I freepour rum and cokes and probably will to my dying day. Jiggers are perfect for more complex drinks though. But I doubt I'd use one to make say a Black Russian.

Oh, & thanks to Erik for posting the savoy guidelines.  I didn't have it in front of me to copy out, but it's amazing how useful it still is. 

Also, for those who have the inspiration, I have a copy behind the bar (for the next week or so, until the regular who lent it to me takes it back) of Trader Vic's original print, which has some intro chapters left out of subsequent editions. In addition to stating some very straightforward rules about building drinks & setting up your bar, the chapters are "How to spot a con artist"; "People Bartenders don't like"; "Bartenders customers don't like";"About mixing & drinks in general"; "Let's be frank about wine".  It's a blast to read.