You can message/post on their profiles of those people and ask what they are wearing. Otherwise we just have tons of commons through out all the shops. Just look through and figure out what you like. We don't have any wishlist applications, people just make threads listing all the items they want. It's nice if someone wants to donate/trade an item to you or just to see what items you like.
I would suggest making a Imgur account (totally free, and if you don't really want to make an account you can just upload images and just not keep track of them) and save images of the avi's that have items you want.
Here is a link to the rare items guide if you want to see what rares we have. If you want to see examples of what is the poses and different items within each of those you'll have to search for the listing on the marketplace to see what ways it can be worn.