The story of mine is kinda unusual, actually. My first fursona, back in 7th grade, was a black and white wolf (like almost everyone's first fursona, if you ever existed on deviantART xD). Over time, deviantART influenced me to change my fursona atleast 20 times (rofl), until I finally quit dA and settled on a fursona (a purple border collie). Or so I thought. Around that time I discovered I was Otherkin/Therian, which began to make me wish I had a more realistic fursona, and so I started messing around with one of my old characters, changing her markings and all that, and eventually she became my fursona. The only change since them has been to her tail, because I keep getting a long, curved phantom tail and so I changed my fursona's tail to reflect that.
But my fursona is very similar to myself. Being an australian shepherd, I love the sanctuary of nature and being in the middle of nowhere. But I also love being around people, and have a funny habit of trying to "herd" people (make them follow me, or go in a certain direction haha), which I didn't notice until quite a while after discovering my fursona. There are a lot of other similarities as well, such as me being a country girl at heart and having total Napoleon Syndrome (I'm short, so I try to make up for it by being tough XD), but overall...it just clicked perfect, and I hope it never changed (especially since I just spendt a crapload of money to commission a realistic fursuit of her haha).
But overall, my best advice would just be to think about animals you like and animals you relate to, and don't worry if you have to change your mind a few times...eventually, you'll "find yourself". :3 good luck.