Simplest way would be to not go there and discourage others to go there as well, but I don’t see that happening.
The biggest thing we can do as tourists is to ensure that we don’t throw plastic and other trash in the open, which is a practice which should be followed at every place.
Another thing I would like to mention is that Ladakh, Leh in particular, is already quite a touristy place and in season, there are more tourists and migrants there than the local population and it has been that way for years. Though till now majority of the tourists were foreigners, which I guess will change soon.
With regards to Leh and few other places becoming too touristy, well I recently wrote “
Taking those extra steps…” in my blog, while it was written with Manali and Goa in mind, it holds true for almost all touristy places and more so for place like Ladakh, where majority of the tourists stick to four sectors, leaving rest of the area almost tourist free.