I am thinking to start own exchange website like (coinexchange.io) , yes I want to build small exchange.
But before start I want to know something , hope I will get my answer.
Building exchange is profitable?
How much investment it's need?
Where I can promote it?
How I can avoid or put low transaction cost?
How much time I need per day behind this project?
If you want to share any suggestions then most welcome.
There is high competition in this area already, so I think it is not going to be so easy to realize.
I suppose other commentators won't suggest you something concrete, unfortunately not I. But I get an idea - you can create an ICO (if only you are not from China) to come true all of your ideas about the exchanger

Creating an ICO without having a any ideas on what you are going to build is useless unless if you build up reputable devs into your team which would somehow assure that the funding would be success but still it would depend on the interest of the community. Starting your own exchange site would really be hard knowing that this thing do really require huge fund and a good team to develop a unique,secured exchanger. If you do have already an idea on what you are going to then you should proceed as long you do know on what you are doing.