The Trio also differ from each other in appearance. They each have different eye colours. Harry has green eyes (although portrayed as blue in the films), Ron has blue eyes (although often portrayed as green or brown), and Hermione has brown eyes.
They not only have differing eye colours, but also various hair colours. Harry has black hair (although portrayed as brown in the films), Ron has red hair, and Hermione has brown hair (although portrayed as dirty blonde in the films).
All three members are related or blood related to the Weasleys, as Ron is a Weasley, Hermione married Ron making her a Weasley by marriage, and Harry married into the Weasley family through Ginny making him an in-law to the Weasley family, as well.