Shareware is a far more competitive market, especialy considering the potencial consumer market.
Things you can do to reach more people are;
Pander to the Lower Spec Market, this is because most people with high end machines are actually cheap and shallow when it comes to thier games. If you have a big label on your game they'll buy it, if not they'll just be happy with the demo.
Multi-Lingual, the more languages and control layouts you cna do few each of the regions; the more people you'll be able to reach.
Exposure homework, find a popular site/forum that you know alot of people who will enjoy your game will be at. Then plug it like crazy with a demo. Then pray for word of mouth
Low-End Publisher, your can't expect your games to just make themselves ... although software download only titles is a nice answer, alot of gamers (like myself) tend to prefer to have a hardcopy which isn't against the EULAs copying agreement.
Durability, although shareware games tend to usually just be piddly little space invader clones and such. The best way to get your game popular isn't through outstanding graphics or even exposure, but by allowing it to get a 'following'.
Games like Neverwind Nights, GTA3 & Half-Life did so well not simply on the fact of their label, but on the fact that you could alter and modify them to create your own version of the game.
Modification communities tend to gather HUGE followings no matter how poor the game actually is to start with, as long as someone can come in an alter it to thier liking there will be a market for it
Graphics, everyone likes thier games not just playing the part, but looking it too. If your graphics are very basic, or don't mesh very well then the overall feel and enjoyment of the game will be let down. And as a game is judged on first impressions from a screenshot, it is an important aspect.
(^_^) even with all of that behind you though you've still got to try to drum up the support somehow, because people might play the game ... but most won't bother paying for it. So you've gotta give them a reason to actually part with cash.
To Survive You Must Evolve... This Time Van Will Not Escape His Fate!