There are some things we can notice that differ a safe site and an unsafe one.
First of all you should pay attention to the URL. If you're trying to access a clothing store website, for example, it should be a simple URL, containing only the name of the store. If it's more than that, you can get suspicious.
Secondly, the layout of the website usually shows you whether it's a safe or an unsafe one. Usually people that create websites with bad intentions don't really care about having a great layout (I said usually, because sometimes they can really make an effort here).