I'm building a movie recommendation system based on genre, where the user will enter his choice and will receive recommendations based on his choice:
First of all, your question is very general and missing crucial information - you should highlight which language and dataset you are planning to use. You should also include it in tags of the post.
Anyway, I suppose that you are working with one of the IMDB datasets. I can personally recommend this article and this article. The authors explain the basic techniques how to build a recommender system in Python using scikit-learn library including cosine similarity.