I'd really suggest looking up a fursona tutorial on DeviantART for help. Usually, a fursona is a representation of you; many people feel that a fursona should share the same gender, interests, and general personality as you. I've even seen a few people who say that a fursona shouldn't own and wear anything that you don't, though obviously you don't have to listen. Those aren't rules, they're just what several people think!
A good rule for fursonas is to NOT do what you see so many people doing in order to be unique. Lots and lots of strange, unnatural markings, rainbows everywhere, and jewellery on every available body part isn't a good way to be unique! In fact, sometimes simple things are the best. Designs are super easy to remember and draw a lot when they're simple.
For example, my fursona is a blonde Canadian Eskimo dog. He has no unnatural markings (though if you want to throw on some, there's nothing stopping you), but he does happen to wear a hat at all times, in both quad and anthro forms. It's not much, but sometimes a new, rarely used species and something simple thrown on might make it stand out more than something with twelve billion scars and doodads. Sometimes giving them a main interest (my fursona absolutely adores Tim Horton's and generally follows a Canadian theme, haha) might make them stand out a bit more.
I hope that helped a bit. c: