Natural and synthetic chemicals like BPA in plastics, Parabens in shampoos and lotions, Triclosan and Triclocarbon in soaps and hand sanitisers, and Benzopherones in uv filters lower Testosterone levels. In addition, added chemicals in processed foods can disrupt hormones in many ways.
For a start, get a BPA-Free water bottle to drink filtered water from instead of buying bottled water from stores. Use only Paraben-free shampoos and lotions and Triclosan and Triclocarbon-free soap. And eat mostly whole foods (vegetables, fruits, grass-fed meat, fatty fish) and avoid processed foods (in cans and packages with listings of chemical ingredients)..