Permethrin. I spray diluted mix onto pants, shoes, hat, and sometimes long sleeved shirt. Let them dry and good to go. Have not has a single tick, since I started doing it.
I have placed 'captured' live ticks onto my pants and they clearly don't like it. They drop off as soon as possible, or eventually die, or at least stop moving. Not sure if it kills them or not, because I crush them right away.