Blogging - Go crazy Blogging about your product/service. Focus on the problems that people are riddled with, and how your Product/Service can be that optimum solution. Once done, share it like your life depends on it on relevant social communities. While sharing ensure that you don't just randomly post your article, make sure that you leave room for engagement
Guest Blogging - do a guest blog on some popular relevant websites. For example if you've build an out of this world wireless charger, then go out to popular tech blogs and request them to talk about it there. Don't market your product, promote the value that a gadget like this could/would offer
Social Media - share this info with your Social Channel and request them to share it across their channel. While sharing it on Social Media make sure that you put out something interesting in terms of the value it offers while putting up the post.
Giveaways - approach some really strong Bloggers and ask them to do Giveaways of your Product on their Blogs. You might have to either part with some money or the product itself but the resulting noise you generate is worth it