What procedure should be followed post spilling fluids onto a MacBook keyboard?
I'm writing this answer in the hopes to dispel the myths surrounding liquid damage repair.  Putting the device in a bag of rice, in the oven, in the sunlight, next to a radiator, heater vent, use a blow dryer, etc. are all nonsense &quot;fixes&quot; that gives you a false sense of security.  You can actually do more damage after drying things out and powering things on following these internet fixes. 
No. Do NONE of this.
The only exception is to turn it off, immediately.

Do not use a towel to &quot;wipe&quot; it up as you're going to spread and &quot;push&quot; liquid deeper into cracks and crevices.  Put it on a towel and pat it dry with (preferably) paper towels.

Do not turn it upside down as gravity will pull that liquid across unaffected areas of the machine

Do not put it in rice or some other desiccant hoping that it will somehow fix the problem.  Rice can't fix anything but hunger pangs.

Do not put it next to a radiator, in the sunlight, or use a hair dryer.  Once you evaporate the liquid, whether by heating or just though the natural evaporation process, contaminants are still left over.


Why?
It needs to be cleaned.
A simple water spill isn't so simple.  The impurities in water are what makes water electrically conductive.  Pure (distilled) water cannot conduct electricity so it actually cannot harm your computer. The problem is water has salts and contaminants and it's this that causes damage to your Mac.
Removing all power and getting it to a competent technician within hours of the spill - not days is the only sure fire way to protect and contain liquid damage. Any other action rolls the dice and can allow capillary action to let liquid seep to every crack, crevice and corner of the device and cause corrosion and short circuits since the battery is still powering parts of the machine when off.
This also is a safety issue if the water gets into the charged battery.
Beverages of different sorts can wreak havoc, salts (metals) are conductive so thing can short out.  There can be acids (juice) or bases (milk) that can cause corrosion.  Corroded circuits can actually destroy components and the traces embedded within the PCB.  For a refresher, take a look at the Mythbusters episode &quot;Salsa Escape&quot; and see what running a small current through the acidic salsa mixture can do to steel.  Now apply that to the tiny &quot;width of a hair&quot; copper traces on a PCB.

How to clean a liquid damaged MacBook
If you don't have the technical skills, don't do this!  Take it in for service.
This needs to be professionally cleaned with an ultrasonic cleaner and electrical solvent.  This requires the logic board to removed, cleaned in the solvent and rinsed in 90% isopropyl  alcohol (not the 70% stuff as there's too much water content).  Then it needs to be dried and subsequently tested.
Can you use cotton swabs and isopropyl alcohol?  Possibly, but it's not reliable.  You'll have better results cleaning the case with this method than you will the PCB or electronic components.  Using alcohol or electrical solvent with a soft nylon bristle brush (toothbrush) will be much better.  You still will want to wash it completely with alcohol and dry with compressed air.
Now, while this will help with the logic board, liquid that happened to get into and in between components (i.e. the glass panes in a track pad) and subsequently evaporated will leave behind whatever residue was in the liquid. This may cause the component to become inoperable. The part might need to be individually cleaned or replaced.
TL;DR

Stay calm.  I know you've just watched your $3,000 baby get a shower from a $6 Starbucks Frap-a-something-chino, but a clear head will help you by not making the problem worse.

Turn off the machine.  No power, nothing to short circuit.

Using lots of paper towels, attempt to absorb as much as the liquid as you can.  Don't wipe; pat or blot; wiping can &quot;push&quot; the liquid making things worse.

Take it for service right away - time is a factor here.  Give the tech full details.  He/she has seen it all and there's no reason to be embarrassed - the more info they have, the better they can get right to the problem and rescue your Mac with a high degree of success.