What I did recently for my job interviews that seemed to help was freezing a bottle of water ahead of time and then right before i'm going to leave for my interview i take it out of the freezer. once i get there i prep myself in the car and take my things, including the frozen bottle of water, and walk in. then i hold it in my right hand and squeeze it till my hand gets really cold. then i would get the people who were interviewing me and switch the bottled water to my left hand quick, right before having to shake hands.
Another thing I did along with this was:
Before the interview i would always sit in the car in the parking lot with the cold air conditioning blasting and put my hands directly in front of the vents.
Hope this helps! Good luck!
p.s.- and after all three of my interviews, they offered me each job. so maybe my hand sweat wasn't very noticeable since i did these little techniques.