You cannot start promoting your product without any planning. If you want to promote your product in a synchronized way then you should know a few things. There are millions of ways through which you can promote your product online but you should know the most effective ways to promote them.
The most common way to promote new your product is to inform your target customers through your website or blog. If you are in the business since a long time and have a website or blog then your customers might check your website and blogs regularly. You can inform them about your new products and its features there. You should make the information crisp and attractive.
Another way to promote your new product is through social networking sites like Facebook, Orkut, Twitter & now Google+. You should keep on tweeting about your new product so that more and more people come to know about it. On Facebook you should keep on posting about the new product. Whatever you do that must be creative and attractive.
If you want to tell people about the product in detail then you can choose to write an article related to your new product and then submit it to article directories. You should remember one thing while you are writing that either your stuff should be "interesting to the people" or "in the interest of the people". You should also mention your website or paste links which take the reader directly to your sales page.
If you want other people to do this promotion work for you then you can ask your associates to bring business to you and you will give them huge commission. You should provide them all the information related to the product through emails, tweets, blog posts, & graphics etc. You can direct them how to promote the product.
You should keep on promoting your product. More you promote the product more are the chances of increasing sales. Consistently promoting your product will always help you.