Hard to give you advice if we don't know where you're at right now, what you've tried, what your in-house capabilities are etc. Are you focused on the Indian market? just your city? or are you wanting to export to other countries?
In general, it is a very saturated market (at least here in the U.S.) The other issue is that trade show attendance and the number of trade shows, themselves, have been declining for over a decade. So it is a shrinking market. However, you do have one interesting option for finding new clients: visit as many trade shows as you can. Usually, there is no charge to walk the Exhibits floor. The companies exhibiting are prime targets for you. The salespeople that you will initially meet are not the right folks, but the people there who are working behind the scenes (typically marketing people) are the right people. If you can work your way through to those people, you could pitch your services/products. The other option would be to scan Exhibitors' lists for various trade shows and cold call into those companies and ask for the marketing person responsible for trade shows. Note, of course, that you will only be one of many trade show vendors who call them regularly hoping for business.
I wrote some stuff years ago promoting retractable banner stands. If you want to see what they look like check out DISPLAYS2G.
Thank you for your reply. This is such a useful piece of information. I would love to read it. I am focusing on the Uk market.