Ways to tickle someone

1. Go for the feet. On most people, the feet are quite sensitive. Be it the toes or the sole, you're sure to get some kind of reaction.
2. The back of the neck. If you do it just right, the person might mistake you for a bug and start swinging wildly to squash it.
3. With a feather. It's a classic, but sometimes it provides the reaction you're looking for.
4. Attack the belly. Especially with children, a good raspberry to the stomach will send them into a fit of giggles.
5. The armpit. Another, slightly sweatier classic.
6. Behind the ear. A light brush to the back of the ear can be quite ticklish.
7. Have an animal lick them. Being licked by an animal can make you laugh.
8. Lightly brush something on their arm.
9. Depending on the person, softly blowing into or onto their ear can get a reaction.
10. Though it doesn't always make a person laugh, you could touch something cold to the back of their hand.