Unfortunately you can’t always wear a t-shirt. There are some occasions where you’d just look like an asshole if you showed up wearing a t-shirt and your favourite jeans. The way I see it, if you’re going to wear a suit, you might as well kill it when you do.
Sure the fit of a suit is incredibly important, but how you wear your tie is just as important, if not more so, because it’s so visible. This article has some amazing tips on how to look great wearing a suit. Some are obvious but some you’ve probably never even considered. Definitely worth a read.