Shopping for men's suits can be daunting, but with a little patience and understanding easily conquered. Comfort, fit, style, and price and most likely the 4 major factors that will influence your purchase of a suit.
The range of suits commercially available to men today is immense, and drilling down to "your" suit via these 4 criteria will make shopping much easier.
First thing to do is narrow down what exactly are you shopping for, this is basically picking the style and color of suit that you are buying.
Color is largely determined by where and when you will be wearing the suit. Formal dinners, business meetings, weddings, funerals, etc.
Price will be your next limiter. There is really no reason to go overboard in this department, but try to get your suit from somewhere that can do basic alterations.
This leads to the next factor, comfort. If you're not comfortable in the suit you're most likely not going to wear it. Also if you don't look good in it what's really the point of spending all the money in the first place.
Lastly, fit, falls back on the previously mentioned alterations. Having a knowledgeable sales person helps here. Correct measurements are key; and a few extra dollars spent to hem a cuff to look like its your suit and not your little brother's go leaps and bounds. Also because of this make sure you invest time, as alterations can take up to a week to complete.