You should really be careful with this. Cutting the cuticles isn't easy and if you use too much force it is easy to cut too deep and then it starts to bleed.
When I am cutting my cuticles I always make sure that I have softened them first by using some kind of exfoliating cuticle cream. Then I cut off the parts of the cuticle that is sticking up or has become to thick.
This cuticle knife is made of metal and comes from Sally Hansen. In the other end it has a kind of spade shaped tool that is good to scrape cuticles off the nail.