<...> my friend told me about the Bitcointalk forum in start working on bounties but not earned any money yet <...>
If you have patience and contribute positively to the forum you will be able to join signature campaign in the future which can give you a more regular and stable income than trading.
The main goal is only based on money, not how to be a member who contributes and provides benefits to the forum. If only money oriented then there will be no development. It even took me a long time to earn money in this forum, anyone who is active and able to contribute and become a useful member deserves to get a reward such as participating in a signature campaign.
nothing is instant, everything requires a process to reach the highest rank and get paid.