I've had some free time since the semester ended, and I've been using it to get some work done that has needed doing for a while. I've been altering some pants (tapering and hemming) as well as lengthening the sleeves on a Corbin Madras jacket that I'll finally wear after years of owning.
I've begun to notice some things about proportion between various parts of a pair of pants/shorts. The overall look isn't so much a matter of the actual width at any point, for instance, but more so the relationship between the width at several points.
For instance, pants that are slimmer and especially tapered through the things, but hang straight from the knees look baggier in comparison on the lower half because of the contrast, and can even appear to flair. This is not a look I'm really into, so I've been taking some pants cut this way and sewing a simple seam tapering them down to take 1-2" out of the circumference of the leg opening. I don't like it to taper too much, because that tends to make your legs look like triangles, but a slight taper is pleasing. Especially with dressier pants, a fairly straight line down the crease looks better than pants that are so tight they make the wide points on thighs and calves seem like lumps of meat in a sausage casing (/skinny jeans rant). If pants are too tight, they disrupt this line and it looks unkempt, and can make you look shorter (longer lines make you look taller).
Here's a chalk line marking a new seam. In order not to mess up the hem, it must be under before the taper and then redone afterward.
Another observation is that the opening width has effects on how long a pair of trousers need to be. First, thinner things look longer, so thinner pants can afford a shorter hem. Wider pants, on the other hand, need to be a little longer. When they are hemmed shorter, you have a big horizontal line hanging over your shoe which looks bad. With a skinnier opening, the pant is closer to the leg, and doesn't exhibit this long horizontal line over the shoe. Likewise, a longer pant will set the bottom of the pant down on the top of the shoe, minimizing this problem.
Some of these same considerations apply to shorts as well. I have one pair that I hemmed last summer because I didn't want them to be quite so long, but now they have a funny look to them. They are very wide, which was proportional to their length, but now looks odd. I'll probably taper them just slightly until that look is gone, then re-hem them.