Most watch bands can be resized really easily.
Several links on the end will have arrows showing which direction the pins pop out. (Crappy picture but you get the idea)

Get something skinny and hard (paperclip sometimes works, something harder might be needed) and set it into the hole on the top of the link. Use a hammer to tap the bar out in the direction of the arrow. Take out as many links as needed, and tap the bars back in the same direction they came out.
If it's a face size problem, look around for a size/shape that looks good on you (rectangular might fit better than round, etc) and use that for a guide when checking out styles. You can always mix and match bands with faces too.