When looking for a skinny jean, you don' want to get them too tight. You want to get them so that if pulled away from the leg, there is at least 1 inch of space between the fabric and the leg. A dark wash is a must in your jean collection, because you can wear them with anything. A dark skinny is especially nice, because you can wear them either casual or dressy. A black skinny is also nice for dressy, but when wearing a black skinny for more formal events, you might choose to get the ones with a bit of a shimmer in them. A light wash skinny looks really good for every day casual wear. Just shopping, or going about town.
For a nice casual-dress outfit, a plain white V-neck T, with a slim fit grey blazer over top and dark wash jeans is a good look.
Celebrity example: Random Model

I personally find that H&M's makes the best fit for a skinny jean, but you can't order them online.
Joe's look:
Black Jeans - Topman
Striped Sweater - Urban Outfitters
Shoes - Aldo