Meditation is a way of finding peace within your inner self and spreading that peace to all around you…
If you can find a group of like-minded people and meditate together then that is better than meditating on your own.  If in such a group you can meditate for longer and be safer.
If meditating on your own it is best not to exceed 20 minutes a day – quality is better than quantity.
It is important for regular times and to use the same quite space as over time a shield of protection can be built up.