A smile is usually friendly and inviting, and a knee-slapping belly laugh usually means your date is having fun. But there are other, more subtle types of body language. Knowing how to read them can help you figure out if your date is really having a good time.
Classic flirtatious moves include touching, smiling, and leaving in close to the other person. We all want to be closer to the things we desire, so moving our bodies forward or usually resting our hand on someone's arm denotes attraction and interest.
If your date does any type of unconscious grooming, like running fingers through their hair or adjusting their clothes, chances are they're trying to make sure they look as attractive as possible for you. If she comes back from the restroom with a fresh coat of lipstick, or he comes back wearing fresh cologne, it's very likely your date wants to get to know you better.
Signs of trouble include crossed arms, turning the body away, and eyes that look everywhere but at you. These are classic signs of someone who is uncomfortable and / or wants to be somewhere else. Be careful however, because some people will not look at you because they are nervous.
The next time you want to let your date know you're interested, remember to smile, usually touch their arm, lean in close, and give your appearance a little attention. If your date is paying attention, they'll get the idea!