Breaking through workout plateaus

Hey guys. So I’ve been working out for the past 4+ months and over the first several months I could see notable gains, however over the past month or so I’ve been stuck around the same weight and strength level. I’ve been following Coach Ellis’s TUFFCUFF Manual and am currently in phase 3 where I work out 6 days a week with two of the days simply focusing on balance and agility. I feel as though my muscles have plenty of time to recover, but am unsure as to what I need to do to break through this plateau I’m currently at. Any ideas as to what methods or techniques I could use to break through?