As of now, not many people use search engines to search for pure hindi topics. But there are many popular hindi and other language sites, which depend purely on English based search and loyal, returning users. May be eventually when the internet reaches the grassroot level people in India, Hindi search will become popular.
As of now, here are my suggestions:
- Use a mix of Hindi and English in the site to get traffic to your Hindi pages from the English search. Separate the English text and Hindi text so that readers who know only Hindi will still get what they need.
- Use English keywords to get search traffic but mix with Hindi in the title/meta description to give an impression that it is a Hindi based site, when the result is shown in search results.
Example: https://www.google.co.in/search?q=meaning+of+chor+in+hindi
- In my websites, I allow posting in Hindi but have made a requirement that there should be a portion in English (preferrably a summary) so that it can fetch traffic from English search as well.Here is a typical site I use to teach Hindi for my kids, that is well optimized for search engines:
http://dict.hinkhoj.com/words/meaning-of-%E0%A4%9A%E0%A5%8B%E0%A4%B0-in-english.html
I could never memorize that site name but I always land there when I search for meaning of any Hindi words.
Also, I believe Hindi websites have a good future and have very little competition.