

Practice your ability to lie and charm people - often, it's just as important as your ability to move without being seen or heard. You want to be able to craft lies, excuses, and personal information on the fly to talk your way past troublesome folks who might interfere with your sneaking mission. In the stillness of the night, you'll be able to hear even smallest movements. For a good test of your ability to move silently, stay awake late at night and try to move around the house silently when everyone's asleep - pick a point in your house to sneak to, then sneak back to your room, going through as many rooms as possible.This exercise improves your ability to keep inconspicuous in crowded areas as well as your ability to control your emotions in the face of someone you've duped. Make sure you keep a straight face - don't give away that you had something to do with it. After you have moved the drink, go back and watch them as they try to remember where they put it. Wait until their back is turned, and then move the drink to another room. Try this exercise: at a social event, watch someone who has a drink out of the corner of your eye.

Every additional person in your surroundings is a variable you'll have to account for - being able to account for other peoples' position and line of vision even when you aren't looking at them using clues like the sound of footsteps, etc. When you're confident being sneaky in small, controlled environments, it's time to practice sneaking in larger, more active environments.
If you can, learn a building's floor plan before hand.Stay near walls when possible - you know you can't be seen through the wall, so you can focus your attention on the angles from which you're more likely to be spotted. You can't see in every direction at once, so in these areas it's hard to keep track of other people and, thus, easier to get spotted. If you need to, crouch or contort yourself to conceal yourself behind counters, trees, skinny pieces of wall, or any other environmental features you can use to block other peoples' lines of sight. Always keep something between you and other people who might see you. The most essential aspect of sneaking is not to be seen doing something bad! Whether you're stealing fries from a friend's lunch or sneaking out past curfew, you'll want not to be seen.
