My 2 cents.
Industry growth I think can be gauged through various means. If the products are used by crores of people, they are visible everywhere, particularly if the products are sold in the country, and as such, we can see a trend emerging or a trend becoming a norm, then I guess the more established players with more reach are the winners, smaller players may grow faster than the established ones, and this could continue for a few years until there is consolidation. If the products are not industry related, and are not directly used by public, then making inquiries about the products’ movement with the distributors, suppliers etc will help. If the products are of B2B nature, then I guess knowing about the client names of all the players will help, these will be available in the respective reports of the companies. And if the products are imported, then following foreign websites will help, which may need subscription.
Depending upon the sector and industry, and even on the company, there are many ways one could assess sales, and in extension profits. Many such businesses are discussed in VP, Avanti, Relaxo, Nykaa, Drone companies, IT, pharma etc etc.
Look everything in conjunction, if you are looking at an industry, including the quantitative aspects of the business, can trusting the management, if a management is perceived to have integrity by the market, and if they are able too, then their statements can be given more weight, and sometimes managements are conservative and do more than they mention, and some talk more than they can give.
All relative, all connected, particularly if one is focusing on businesses which are of new age, or trends are starting, because these could take time to come to fruition, so patience may also be required.
I don’t do all of the above mentioned things, because I have started focusing more on shorter terms, so take my thoughts with a pinch of salt.