I'm writing an article about a cat saving a three-year-old girl's life. So what tools/techniques can I use to keep the reader interested?
There is many things you can do to make a story through a cat's perspective compelling. There is great potential for witty moments, thrilling moments, interesting moments and even heartwarming moments. I say "even" because cats are the pet equivalent of psychopaths (or sociopaths). They care about themselves, as is their nature, shaped by evolution since they do not need to care for other individuals. It would be obstructional for them to care. They're not flock animals, therefore not social animals, hence their natural lack of empathy.
But that's a digression. You can either play on that point, or subvert it. Make your cat unique in the way that it is selfless (as Sriram said). It does save a child's life after all. But then again, this could be because of self-centered motivations, or even by accident. What I really meant with this point is that you should read up on the animal. Know its behaviour and quirks, because that is the only way you can truly write from its perspective. I find stories with elements centered in truth much more compelling. Of course, it would be unrealistic to try to make a story like this realistic. —It doesn't need to be either.
As I mentioned earlier, the potential for humour, thrill and curiosity is unending. The humour can come from the cat's selfish, nonchalant and apathetic outlook on life and the people around them. Thrill can come from the many dangers a cat must endure. If in the city, there's lots of scary stuff creeping in alleyways, and cars zoom past on the streets. If on the countryside, there's lots of scary animals that can harm your cat e.g. eagles, badgers, coyotes and not limited the the countryside, humans.
Cats are also naturally curious, as it is beneficial to their opportunistic lifestyle. Whenever a situation calls out the curiosity in the cat MC, you have endless possibilities for mystery, curiosity (within the reader), anticipation, etc.
Catacylism and catastrophic story will set forward when you categorise your cat story. Cast the cat as a catch 22. Load the story gently and meld the characters. The mostly useful part in this story line is selfless cat life. It grows near owner and serves the master when it's the highest need. Non fiction would have been my choice if I was it's writer. Take a leap and act like a cat, start.