Hello JashimChando and welcome to the forums.
It really sounds like you are beginning to study the market...goood.
Of all the machinists I know there was not a single one that had such a magical beginning, all studied hard, worked in someone elses shop or a big company, learned some more and gained experience, bought/restored/upgraded used equipment, held two or more jobs while cranking out parts on the side, and only then...once they made proper connections, received excellent recommendations, and stuck their heads into a various communities that would require his services - finally be on his way to doing some business in his own shop.
Holding different positions in various shops will allow you to study the market up close with all the benefits of still making a living.
Of all the investments that I can think of, the most important one is not going top be location, neither it will be how well you advertise, nor even and (especially not) the equipment... the most important one will be your education
(buy books, read forums, read and talk, read and talk, etc etc etc), experience, and skill in producing a lot of excellent work and doing it fast(or at least sticking with the schedule) no matter what happens.
Where to find customers?
What can be a better advertisement than a - "good reference from a happy customer" ... don't forget to send them birthday cards(yes cards, not e-mails)
As for investors and partners ... well ...
I may be opening my mouth too wide here, but I think it is not a wise move to seek a partner/investor simply because - "Having a PARTNER IS HAVING A BOSS" ...being your own boss is light years away from having to answer to someone about each and every penny spent...I'm my own boss and this is just my opinion.
I tried to gather all the questions you asked in other topics and answer them here as honestly as I could and I wish you all the best in your beginnings. Good Luck!
PS: I'm currently researching equipment and getting ready to buy my first machine, so good luck to both of us.