I am a software engineer in SNIPPED. We are going to launch an online website as one of our product soon which relies its income purely through online money only.But we are not well aware of how to capture big advertisements.Hope a reply would be posted soon,Thanks.

I don't really undertand what you mean. Are you selling a product and the only advertising you intend to do for this product is web based? Or is your website the product and you want to use it for generating advertising revenue?

Make a press release about your product and give your site a good start with SEO..

Your advertisements must be clearly directed to your market niche.
Many ads have failed because their market niche were not able to get the message of the ad itself.

Create press releases, article and submit them to article directories. Make a blog and write posts optimized for specific keywords. Try to offer your service for free for a short period, in this way the service will gain more exposure over the internet.

Make a banner and placed it in top site for instant traffic and business.

I dont think u looking for traffic...
However if you are looking for big advertisement then i will say that Google adsense has no alternative....