My MacBook Pro HD Storage Capacity is getting full with majority of usage classified as Other (126.77GB). What is included as Other and how can I edit and delete unnecessary content?

The Storage capacity on my MacBook Pro (Mid 2010, Version 10.10, 4 GB Memory) is getting full. It appears I only have 29.04 GB free of 319.21 GB. The majority of usage is classified as "Other" (126.77 GB) and "Movies" (106.05 GB). I would like to edit and delete some of the Other content, but what is included in this category? How do I know what is safe to delete? I don't have many documents created. I have saved and filed content from internet sites... do these type of files use a lot of storage capacity (mostly recipes)?

I have very few Apps and have been updating all software regularly. Mose recent update was Yosemite.