It is usually harder to be seen if you are small youtuber no matter how great your tags and descriptions are or how popular your video game of choice may be or just video in general youtube has way more people now then it used to when it started and well video gaming channels are overpopulated so seo does help but the more views and action your videos get the higher ranked you can get. People with a lot of subs will also rank higher unless you play something noone ever does it will be hard to be seen just keep doing what your doing for a little while and see how well it works. If it dosen't work the way you want keep trying new methods until you find one that works for you.