Digital marketing strategist with over a decade of experience and half a dozen certifications with a Bachelors Degree in Internet Marketing in the works. I'm also an Infusionsoft Certified Partner and a Digital Marketing Certified Partner.
Have you considered utilizing a tool like Webinar Jam? You can pre-record your webinars, turn them into evergreen webinars and set the entire system up to provide specific dates and times for the recording, including a, "Your in luck, our next one starts in 15 minutes!" option or something like it.
Three weeks is a long time to wait when we are a society that want instant gratification so offering something like this may be a key for more frequency.
Also, if you have a way to monitor the open rate of those five reminders, I'd encourage you to look at that statistic. Even though your current schedule is three weeks out, five reminders seem a little high and I'm thinking you'll see that the two out of the five e-mails don't even get looked at.
Other suggestions would be to look closely at your webinar title, the length of the webinar and even the hook you are pitching to encourage people to watch. You want to give off a high perceived value to entice registration and attendance.
I'm a Digital Marketer Certified Partner and they have some pretty valuable videos and material regarding e-mail marketing. You might want to look at some of what they offer, especially the 101 Best Email Subject Lines of 2015 for inspiration. Here's the direct link: http://www.digitalmarketer.com/101-best-email-subject-lines-2014/.
The one piece of advise I'd give to you, and anyone else, is to get that double opt in and make a big effort to teach your consumers how to whitelist / add your e-mails to their address book.
With Google it is helpful if they star and tag your e-mails. Google learns what you want in your primary inbox and what you don't by how the tool is used. Providing highly valuable content to your audience will help keep engagement up.
Hope that gives you some places to start.
Have you thought about suggesting existing Customer Relationship Management (CRM) platforms? While they all have learning curves to tackle, they will still surely be time savers compared to starting from scratch.
I'm a big fan of Infusionsoft and a Certified Partner but if a robust solution like that is too big for your needs then there are others like Hubspot CRM or even Insightly.
They each manage contacts like a boss however they will each also have certain pros and cons that you'll want to research for your specific needs as well.
Many popular social media platforms have advertising platforms that can be zeroed in pretty well. For example, Facebook would allow me to select, "People traveling in this location" and then India as a country or specific cities within the country.
I wouldn't just assume that Facebook is the end all be all answer for your question though. You should do some research on which social platforms are popular in India right now and then explore those for advertising opportunities. For example, I came across this article that you might start with: http://www.insidermonkey.com/blog/10-most-popular-social-networking-sites-in-india-357564/
You can utilize Facebook ads to measure interest from the target market you think would utilize what you are creating.
A landing page showcasing how your product can solve a consumers pain points followed by an option to receive updates via e-mail about the product would be the best direction to start with in my opinion.
Also, remember that not everyone will sign up for your interest list so you'll want to setup a Facebook Pixel and then an audience. By doing this you can later send out a completely different Facebook ad to everyone who viewed the page regardless if they provided information or not.
Hope this helps!
I'm reading a book called, "Disciplined Entrepreneurship: 24 Steps to a Successful Startup" written by Bill Aulet.
The 24 steps are broken down into six categories:
1: Who is your customer?
2: What can you do for your customer?
3: How does your customer acquire your product?
4: How do you make money off your product?
5: How do you design and build your product?
6: How do you scale your business
Your technically asking a good number of questions and I'm thinking this book might be a good starting point for you.