The US, India, Australia and Japan grouping should firm up a plan which goes beyond the usual joint statements of intent.
The first and perhaps the most ideal way is to get the Americans start investing more in geograpies where Chinese have invested like nobody else's business. It's natural that small countries tend to hedge China with other countries. But a concerted effort is needed to check China. For that Quad need to show that it is a group that can improve lives of people in the region. Bring credible alternative to China's supply chains, including tech supply chain.