Choose wine that you know has real wooden corks rather than those cheap plastic ones. It’s hard to tell unless you’ve bought the brand before, but you can use CorkWatch by Re-Cork - a database of wines from all over and tells you ‘natural’ or ‘plastic’ corks. You can even add to the database if your wine isn’t listed.
Cork has shown to keep the flavor better in some cases, and the cool thing is that harvesting cork is actually HEALTHY for the trees and supports local commerce in regions like Portugal. According to Corkforest, cork is the most sustainable and renewable forest resource.
Support the cork industry by buying wine and other products that use cork and when you’re done, ship it off to be recycled into new products.