For future reference, don't power up a wet laptop. Remove the battery. Now lazy me was going to type further instructions, but it was easier to Google and this is what Digital Trends said to do:
Step 1: Remove all easily detachable components. Unplug your mouse and any cables, and remove any flash drives and DVDs. Leave your laptop bare.
Step 2: Dry the outside of your machine. Open your laptop as far as it goes, hold it upside down to let any accumulated liquid drain out, and use an absorbent towel or a lint-free absorbent fabric to wipe wet surfaces until they're dry. Do not try to dry the computer with forced hot air from a heat gun or hair-dryer.
Step 3: At this point, we recommend that you take advantage of the warranty if it's still applicable or take your machine to a repair shop. If your brand has a designated repair store (like Apple), give them a call or take it in. Otherwise, look for local repair stores that specialize in your laptop brand.
Step 4: The type of liquid that was spilled matters. Water is the least acidic, while sugary and alcoholic fluids are more conductive and more corrosive. They can quickly cause permanent damage to your internal components. Either way, the goal is to mitigate their effects as much as possible by drying the computer immediately. If you don't want to have a professional take a look at it for you, though, there are more steps you can take to try and dry your machine out. However, please take note that neither Digital Trends nor the author is responsible for any damage caused to your PC by taking it apart.
I'll now add that you can use a fan to help dry and I wouldn't try to restart for at least 3 days.