There are many techniques to protect yourself from karmic intrusion. Imagine your hands as blades and slice away around your body to sever any connections. Stay grounded. Hang decorative glass balls about your house to trap negativity.
In the psychic community, the most common technique that most people know of is the Psychic bubble (the great technique with the really stupid name) and everyone has their own way of creating a bubble. Here's one technique.
Begin by opening your chakras. A Chakra is an energy center in your body. You've got them everywhere. The seven main ones run through the center of your body.
This is the technique which I use for opening my chakras. I do this any time I can focus on the intention of seven breaths; often while driving. Start by visualizing the seven chakras
The base Chakra (first Chakra) is at the base of your body, and extends into the earth, its color is red
Your sexual (second chakra) chakra is at the level where men wear their belts. It's color is orange
Your personal power chakra (third chakra) is at your solar plexus. Its color is yellow
Your heart chakra (forth chakra)is at the level of your heart. It's color is green
Your communication chakra (fifth chakra) is in your throat. It's color is blue
Your third eye (sixth chakra) is in the middle of your forehead. Its color is either indigo or violet
Your crown, (seventh chakra) is at the top of your head. Its color is white.
The following meditation can be done any time when you can focus on 7 breaths. You don't have to close your eyes, so you could do this while driving. Any time when you can take 7 breaths and focus on the intent of 7 breaths
Breath in and visualize a red light at your base chakra. Breath out and let the light grow brighter
Breath in and draw up from the red light to your second chakra and let it be orange. Breath out and let the light grow brighter
Breath in and draw up from the red light through your second chakra to your third chakra and let it be yellow. Breath out and let the light grow brighter
Breath in and draw up from the red light through the other chakras to your heart chakra and let it be green. Breath out and let the light grow brighter
Breath in and draw up from the red light through the other chakras to your fifth chakra and let it be blue. Breath out and let the light grow brighter
Breath in and draw up from the red light through the other chakras to your sixth chakra and let it be indigo. Breath out and let the light grow brighter
Breath in and draw up from the red light through the other chakras to your crown and let it be white. Breath out and let the light flow over your entire body, covering you with white light.
Once your chakras are open, feel the power in your third chakra (solar plexus, yellow). Allow the power to extend out to your hands. Hold your hands as if you were holding a volleyball, and the feel the power flowing out into the shape of the ball. If you squeeze the ball, you can feel it resisting against your hands. Energy flows up through the body, so take the energy ball, and put it back into yourself through the base chakra (bottom of the body, red) and allow it to flow all the way up to the top where it comes up and covers your body in white light. This establishes your ability to work with your third chakra, and gives an extra boost to train the system to have smooth upward energy flow.
Look again to the third chakra. Now this time imagine the glow, the size of a cherry. Breathe in and it gets brighter. Breathe out it grows to the size of a baseball. Breathe in and it gets brighter. Breathe out it grows to the size of a cantaloupe. Breathe in and it gets brighter. Breathe out it grows to the size of a medicine ball. Breathe in and it gets brighter. Breathe out it grows to be large enough to encompass your entire body during jumping jacks. Breathe in and it gets brighter. Breathe out it grows thicker and more resilient. Nothing can get through. You are safe from psychic attacks.
To close your chakras (if you want to close your chakras) use the same meditation in reverse. 7, 6, 5, 4, 3, 2, 1 all the lights are out.