As far as I can tell, every serious health professional in the US and abroad says that more testing is the key. The sooner you identify people who have the virus, the sooner you can get them into isolation and disrupt the transmission chain.
Anyone who has been in contact with someone who has tested positive should be tested as soon as possible. Results should be available quickly as well. Time is essential to get this under control as soon as possible and have things return to normal.
A lot of testing in conjunction with lockdowns, social distancing and face masks has proven effective.