AskMen.comI'm really lucky to be working in an office where everyday is casual Friday [fashion-wise only :)], but for those who have only one casual Firday a week, the above link provides some advice on how to pull off a stylish yet casual look with jeans. One thing I'll add to the advice; if you find wearing a T-shirt with jeans to be too casual, one solution is to pair it with a long sleeve shirt. There are also several options on how you want to wear your shirt; with sleeves rolled up, just the cuff folded, shirt tucked in (or out), top button unbuttoned... Go forth and experiment.:)