I'll give you a legit response, although it sucks you didn't give your body type:
You need good jeans, check out: APC New Standard, Nudie Slim Jim, Naked And Famous Slim Guy. These are all dry jeans, they'll be about $150-200, but it's completely worth it. These will be your jeans, you will wear them daily, and not wash them. It seems weird, but it's the cool thing to do. Your jeans will turn from being a classy dark indigo into badass fades in a couple of months:
Photo from Poly800rock, showing excellent hand made Ande Whall jeans:http://farm3.static.flickr.com/2457/...c6b38f51ee.jpghttp://farm3.static.flickr.com/2668/...2fcefb14c4.jpg
Shoes are extremely important, many people underestimate them. If you're as fashionless as you claim, you probably are wearing some new balances or something right now. For a cheap fix, converse all stars and vans authentics are nice. Don't get any screwy colours or patterns, white or black. Don't worry about expensive sneakers right now, you'll buy them on your own accord when you're ready for them. Winter is approaching as well, and being in Canada, you'll need a decent pair of boots. I wear LL Bean Kahtadin:http://www.styleforum.net/showpost.p...9&postcount=56
On the top portion you just need to make sure it fits. There are some easy nice outfits. I like a white polo under a deep coloured cardigan, such as burgundy, purple, or gray. Paired with dark slim denim this works quite well. However, it must be worn as slim as you can possibly wear it, no more than 2" or so wider than your chest is. It is important to know your measurements. Provided you're not emaciatedly slim like many people on this forum, including myself, are, you can probably find well sized sweaters or polos at JCrew, and American Apparel makes quite decent slim fit cardigans with very well shaped slim arms. Don't buy into brand hype, just because it is $100 and has an alligator on it doesn't mean it's a great product, wear what fits your body.
The key points are to keep it slim and keep it simple. If your clothing fits properly, is colour coordinated (not hard to do with jeans,) and is not gaudy, it will probably look good. Get the basics down before you try anything crazy.