Wide leg trousers will make you look shorter if you get the length wrong, and the margin for error is smaller than it looks. Too long and they pool over the shoe and eat your whole leg line. Too short and you get an odd cropped flare that reads more painter and decorator than anything else. The window where they actually work is about half an inch wide. Still worth finding, because when it's right, nothing else makes a leg look longer.
If you've got none, start with a pair in a heavier, stiffer fabric rather than anything floaty. A floppy, slippy wide leg needs its own momentum to hang properly, and most of the budget versions don't have the weight to do it, so they just cling and crease instead. A proper suiting feel, even a cheap one, holds the shape from waist to hem without you having to think about it. Go for a straight, consistent width from hip to floor rather than anything dramatically flared, it's a more forgiving starting shape and it works with more tops.
These earn their keep in fairly specific windows, oddly. Autumn and winter, worn with boots underneath so the hem skims rather than drags on pavement. They're also quietly brilliant for anything a bit formal where you don't want to commit to a skirt, a work thing, a lunch where you'll be sitting down for two hours and don't want a waistband digging in. I would not choose them for a long walk anywhere hilly or wet, the hem picks up everything and you'll spend the day looking down at your own ankles with regret.
Fit is almost entirely about two things, the waist and the length, and the waist matters more than people admit. A wide leg hangs from the waistband with nothing below to hold it in place, so if the waist gapes even slightly, the whole trouser sits wrong all day, twisting and dropping an inch at a time. Sit down in them before you decide anything, that's where gaping shows itself first. For length, with flat shoes the hem should just graze the top of the foot, not the floor. With heels, try them on in the actual heel height you'll wear, because a flat shoe fitting will lie to you completely.
Do they sit at the natural waist without gaping when I sit down, and does the hem actually reach the floor in the shoes I'll wear them with, or only in the flat ones I tried them on in?