re:there are several ti...
there are several tips when useing IT (Invisible Thread)
Wear dark cloth (Black)
Do not wear anything shiny
Perfrom maigc with distance up to 6 feet (I don't know how far tha tis in meters)
Try to secure the IT somewhere else rather then teeth (I put it behind my ear and directly come down to my shirt, when I need it, I use my hand to support.)
There are some good IT you can get off penguin magic, the quality is pretty good and less light reflection.
There are some new kind of flat IT where it doesn't reflect light and also it streshces up to 5 times its original length.
ITR (Inivisible Trhead Retractor) is used to pull the IT back so spectators can examn the card after.