This is a very simple technique that can be done as part of a meditation or as a process alone.
Sit quietly. Center yourself. Take 2 or 3 cleansing breaths if needed. I refer to the guides who do this for me as my guardians. Call on any deities, protection guides or angels that you work with.
"I ask my guardians to place a cocoon of protection around me." Sit for 20-30 seconds as they do this. If you are sensitive, you may actually feel them doing it.
"I ask my guardians to place another cocoon of outward facing mirrors around that." Again, sit for 20-30 seconds while they do this.
"I ask my guardians to wrap a cloak of invisibility around me & pull it in tight." Sit with the experience.
NOTE: A lot of times, for just day-to-day running around, I just ask my guardians to come in & fill up my aura with invisibility. For more difficult situations, I'll do the entire process.