Buying Clothing Online: A do or a don't?

I read all these great blogs with ladies who show off their awesome style and I am always amazed at how many of them purchase their clothing online.  Asos is one I see show up a lot. The thought of purchasing clothing online brings up mixed feelings for me. Is anyone else nervous as I am?  The few times I have ordered clothing online I have ended up returning it because of fit issues.  Now this big booty, small chested, short white girl (aka me) doesn't look good in everything.  Now I have been looking for a grey pair of jeans for awhile. More like foooreverrrr.  I was on Gap's website the other night and noticed that they had a pair and typically Gap jeans work well for me.  Plus these bad boys are on sale.  But to me shopping for jeans is like shopping for a bra.  You have to try 5 of them on to get one you like.  So I went out on a limb and ordered a pair..  Wish me luck.

Oh.. and this too. It just screams fall to me and I am a sucker for a black cardigan