Well the title says it all doesn't it? Presentation is everything!
You could design a game which had a possibility to win major awards and get a look in by large computer game firms, but if you rush it; people can be put off and you lose out on the amount of downloads it recieves. Here are a few tips to help you get the most out of your game:

TAKE YOUR TIME
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I think I speak for most people when I say this; Your designing/programming a game and you are dying to get it released so others can see it and you can be told how good you are for making such a masterpiece, but if you rush parts of it so this goal is achieved, the final outcome may be of less quality than you had hoped for.
What I say is dont rush. Think of it this way. Even if it does take a week or so more for the final release to come out, the quality will be better and the players will thank you for that

TEST YOUR GAME THOROUGHLY
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Always do! The more you test your game, the less likely errors are to occur. And get other people to test it too. I have actually found that other people come across errors that I havent seen first time, and so can be immediately rectified.
Is the game playable? Does it work how you intend? These questions all get answered as you test your game

POST A PREVIEW
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If you wish to let people know about your game ASAP, then post up a review. This will get other peoples mouth's watering and at least you know as you make your game, people want to play your game. You can also ask for ideas which can always be a bonus! A lot of Daily Clickers are happy to post up ideas for you to incorporate into your game

FINISHING TOUCHES
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Make a good and reliable installer, clean up your sprites and post up a good overview of the game when you post it up for download.

I hope this has been of some help, and if some parts are hard to understand I apologise but I write this hal asleep