A combination of proper tags, titles, descriptions and thumbnails are very important! For example, there are tools online that allow you to check which tags (and other tags related to them) have the most searched-for percentage versus how often they are used, giving you an average percent of how effective a tag might be for your video. Checking out these stats may seem like a bit of a pain, but considering it's ideal to use between 5-7 per video, it's not that much work.
Titles are the same way. Catchy ones, relevant to your subject matter. Descriptions as well, and try to use some of the aforementioned tags in the description in a paragraph describing what your video is about. Thumbnails are very important too. Titles placed away from the time stamp (so the words aren't blocked in feeds), nice design, unique fonts. Something eye-catching.
Commenting on videos relevant to your channel and engaging in that community on YT via collaborations are great too.