Firstly thanks @pawanain.. you are kind with your words..
Actually I did 2 things for increasing my repo..
In the initial stage when my repo was 25, I found whales (guys with over 77k steem power) and interacted with them on their posts.. The are generous and do upvote on our comments.. so using this technique I could raise my repo to around 36.
After that I realized gaining repo becomes increasingly difficult so that wasn't sufficient, so I did some investment .. and gained upvotes using bot .
So you can try both methods or either :)