Here are some of the answers to your queries.
1. Honestly if writing is not your passion, you'd only earn from spamming the content. Which won't last for long. You'd only earn for long if you have developed your personality around it. Then writing and the revenue becomes natural. There are people who are pumping content by using ghost writers and making money but that would soon fade eventually. Passion matters. Even if you get robot to write the content, people pay for emotions, not machines spam. Think about it, would you pay a robot for greeting you happy birthday during birthday party or would you prefer real people? That's why passion and people matter in writing profession.
2. Many writers learn as they move up in the ladder. Some writers do make mistakes which editors and scribe cover up. But it's good to be having command over English. Sometimes concepts themselves are not enough. It'd be good if you learn to hold command over English as you progress ahead with your projects.
3. You need to understand your focus for the writing. If you can write urdu better then stick with that. In that case you have to find means to write for revenue. If that is your goal to write at first place. Most likely you'd have to work harder either way.
4. Writers usually write the draft, send the stuff to publishers and then they polish the content. Once that is done, the next part is to market it. The type of marketing decides if your book ends up in favorite list. Often some good reviews can change things too. But it all comes down to the content you write.