Améliorer, vtr : to improve, to make something better.
S’améliorer, v pron : to improve, to get better.

Cette loi a amélioré la situation des enfants.
This law has improved the situation for children.

Dix minutes d’étude par jour pourraient vraiment améliorer votre français.
Just ten minutes of study a day could really help your French.

Cet apprenti s’améliore de jour en jour.
That apprentice is improving every day.