First, the Spotlight index is easily broken and when that happens files that should come under the label or Movies, Audio, or whatever default to Other. Second, Other is everything that doesn't fall under any of the labeled categories. While it makes sense to ask, "How do I delete Movies" it makes no sense to ask, "How do I delete Other" because other is so many different things - some of which you do not want to delete.
If it helps you to know how much space is being taken by various file types you can (temporarily) rebuild the Spotlight index using the link Klaus1 provided. (I haven't bothered for ages.) There are shareware and freeware programs that can help you find this information more reliably. Free: OmniDiskSweeper. My favorite shareware program is DaisyDisk (I receive nothing for recommending it).
Finally Klaus provides a good link for releasing space (assuming you are using Sierra or High Sierra). A quick way to free up space is to move video, movies, and music to an external drive.