The point of this article is not to get you all starting up companys or anything like that but just to give you an idea of how a few small touches can help a game greatly.

Don't you just hate badly slapped together menus with a couple of ugly buttons placed in no particuallar order or place with overlapping text and things hanging of the edge of the screen. I know I do.
The mian menu is one of the first things the player sees and so has to look good, inviting, attractive. Think about where you should place text and buttons, give them some kind of set order or something. Making your own buttons out of active objects looks alot better than a grey rectangle and can be easily done as well.
Make sure your buttons work or else don't put them in there, if there is a feature that's disabled in the demo put "disabled" next to it or grey out the button.
That's all I'll say about The mian Menu for now.

Moving on, don't you just hate it when there seems to be no clear way to start or exit a game. If you get rid of the Windows Title bar then make sure you have another way to exit, othewise the user has to use Ctrl+Alt+Delete to end the programm which is an off-put. Make it clear how to exit or start a game and the user won't hace to spend time quessing.

Now the programming side of thiongs
If your game has a bug you can't fix that you know about, tell the player that, it can help the player aviod doing things that may crash the game etc.
Everyone is at a different level when it comes to the programming but you must still always try your best. Check over your event list for any conflicts etc. It's easy to let a bug slip in somewhere.

We don't all have Sound Blaster Audigy Platinum Sound Cards and exspensive Sound Creation/Editing Packages such as Cool Edit Pro 2. If you don't that doesn't mean your sounds should be utterly crap. Make sure there the right volume at least, you can do that with the limitted sound recorder supplied by microsoft in the Accesories menu.

Graphics:
We can't all draw but we can all make sure things don't overlap or look stupid. Check that things don't look really bad and stupid and you don't have to be an artist.

I could go on for ages but you get the idea by now.
Hope this helps someone!