Most of the forms have to be filled with your own information,So you have to do this by yourself. Any organisation or person will give you a high invoice for the work what they do, but they will only fill the information what you will give them. Also you have again to reach all your information, Thus the same work, only a high payment to you.
Many thing you can do in advance, English test, birth certificates, renew passport, even all the required paperwork. After you get a invitation you have 60 days to reach the whole package to immigration. So be prepared.
I did all by myself, you need a lot of time, many readings, and a proper, complete application.
That's it.
I live close to Delhi.