Let's start with the basics. Fit is a rather generic term as it covers not just length and width. It includes straps, buckles, heel placement and arch support also. And since you will likely wear them barefoot you need to try them on that way. A pair of thin socks or disposable 'peds' will do if you haven't yet reviewed our hygiene section. Next you need to figure out what kind of feet you have.

Narrow = Slim, shaped like a pencil. Skinnier at the heel is a common concern.

Medium = Neither thin nor wide. Also called the Goldilocks fit.

Wide = More boxy than not. Shorter toes are common in wider feet.

Extra Wide = You already know if this is you.

It's important to be aware of what width you need because sandals that are too narrow will pinch and you won't wear them. Too wide and your foot will slide all over the place and cause fatigue so you won't wear them either. Additionally don't forget to consider whether your feet swell. If the sandal doesn't adjust to your needs they're not for you.

When new sandals hurt, slide, rub or in are in any way uncomfortable move on to the next pair. The perfect fit is often hard to achieve but it's not impossible if you know what to look for.

Once you know your foot type, it's all about the foot bed and straps. When possible pick up the sandal and look at where your foot will land before you bother trying them on. If you know what to look for you'll be ahead of the game. For example, some German brands run wide. Why? Germans have wider feet (a generalization but on average it's true)