Most people find that it takes at least 20 minutes for the mind to begin to settle, so this is a reasonable way to start.
The effects of mindfulness meditation tend to be dose-related — the more you do, the more effect it usually has. Most people find that it takes at least 20 minutes for the mind to begin to settle, so this is a reasonable way to start. If you’re ready for a more serious commitment, Jon Kabat-Zinn recommends 45 minutes of meditation at least six days a week. But you can get started by practicing the techniques described here for shorter periods.