I just read Rock Girl's guidelines for protecting your energy. Here are some ideas. Rock Girl offers stone readings was on Psychic Air Radio's website. I will be hosting my show "Dr. Lily Listens" on May 25, Tues at 6pm PST, 9 EST on Psychic Air Radio and am excited to meet all of the callers.
1. Wash your hand after touching someone.
2. Carry Black tourmaline or Black onyx works to cancel negative energy.
3. Place myrrh on back of your neck.
4.Take off your shoes when getting home.
5.Take a shower when coming home.

I personally envision light, (any color so as long as it feels nurturing, the only color I dont use is red for this) around my home, office, belongings, myself, clients, family, friends. Ultimately I then ask for energy protection for the  world and planet. It feels good to do it and I feel much more protected afterwards. This is especially effective with driving. Nowadays many drivers are reckless and drive too fast. Picturing light around you and sending them light immediately changes the situation for me. This is why I do it all the time. Let me know if you hear of anything else that works. Sage and crystals around the home always is effective too.