based on my experience I suggest the following:
1) Shut down the device immediately
2) clan up as much liquid as possible. If you have a small vac you may be able to vac some liquid out.
3) Let the MacBook dry out in a well ventilated area. DO NOT submerge it in rice the particles acan get into the computer. You can place rice or a dessicant under the computer to help absorb water.
4) WAIT at least 24 hours to try the power up
5) If it powers up back up your data
6) Take it to a liquid spill specialist for Macs that is Apple approved. If water has gotten in it may work for a while then slowly die due to corrosion.
7) The repairspecialist I used was Apple authorized. They charged $480 flat rate to fix the problem like new and revalidate the Mac warranty I had purchased. They ended up having to replace the screen and logic board even though my macBook Air did temporarily power up post spill. I essentially got a new laptop and my warranty reinstated for the price- a more than fair deal. The likelihood that the damage is slight is small. If there is no damage, they will tell you and not charge you.
I used Expert Mac Repair which has offices in DC and Chicago. They were great and people mail work to them from all over the country. The repair took 6 days and they sent me all my files the first day so I could do my work.