In college, I always knew I was going to be tested before SECs/Nationals, so I would make sure I was taking nothing but testosterone and maybe EPO, GH, etc, which they wouldn't test for anyway. At elite level, depending on your sport, you might be able to get away with low dose test. proprionate at the time of a test, but not if they have made the switch to carbon ratio isotope testing which can determine synthetic from organic testosterone. If that's the case, designer steroids or try testosterone cream - or you move up to GH/IGF-1, Insulin, etc.
But, yeah, know you clearance times, too!