What can I do/take to boost testosterone?

+exercise / -alcohal. Increasing your exercise routine(s) and eliminating alcohol would be the best natural boosters for your testosterone. Avoid testosterone supplements, especially in oral forms: first pass metabolism can result in peliosis hepatis/hepatitis/hepatocellular carcinoma. Exogenous trt will likely lead to infertility, and a permanent dependence due to negative feedback inhibition.