First of all what will make our software a success? The ratio between quality and price is what will make your software good or bad, you must see what the market offers compared to you. Browse download.com for software with capabilities similar to your: how is their price compared to your? If your is more expensive then reduce its price or add more functions.
Ok, your software has a nice price then how can we promote it? First step is to create a demo of it, you can make one that lasts for just a number of days or another that stands forever but with limited functions. There are many software sites that will let you upload your demo and so many people will download it. To find them just search Google by "shareware", shareware is a term popularized by Bob Wallace and that refers to copymitted software shared on a trial basis without payment and that is somehow limited in its duration or functionality. Depending on what kind of software you have developed you can make it that just offers some useful functions while the most are featured only in the full version, this will let your trial software stay for a long time in the computers of your potential customers and in This way they will always be linked to you and maybe a day for increased needs will buy it.
The shown above is not the only way you can promote your software, you can start also a Google campaign and offering the download of your demo in your sales page that is the page in which you sell your product. You can optimize your sales page for a certain keyword or for a certain phrase, to learn to do this you can use many of the free SEO guides available online and that can be found searching Google by "SEO guide": SEO is the acronym of Search Engine Optimization and your optimized page will bring you more visitors and so more sales.
Another powerful way to promote your software is using affiliate networks in which every affiliate for each visitor or customer that they are able to bring, this is a way to promote your product in a viral way and do not forget to mention the possibility to join as an affiliate in your sales page or even inside the software itself. Some networks ask for a fee while in other subscription is free of charge and you pay just responsibilities. Any if your product sells well then will be ranked well in them and so more affiliates will promote your software.
All said before shows how important is your sales page and so it's very important to give it good graphics, appealing explanations, nice screenshots of your software and buttons for the buying and for the download. The techniques explained before can be used at the same time and work in sinergy to give you the best. With tools like Google analytics you can monitor them and so realize which one gives you the best results so you'll be able to also adjust your marketing strategies to achieve your goals.So start now to promote your software, i wish you many sales. ..