No, I just put terms that are not that popular. It's working now

So, I got this video: The Walking Dead Game Tribute Song | ORIGINAL TRIBUTE SONG | A Song About The Walking Dead..... The tags I put: the walking dead game, the walking dead theme song, let's play the walking dead, clementine and lee tribute, music for the walking dead, a song for the walking dead, a song about the walking dead, the walking dead game soundtrack, telltale games, tribute song, original tribute song, clementine, lee, tribute, the walking dead music video.... (and so forth) Are these good tags? It actually ranks me no.5 when I type: the walking dead tribute song
The last bit of your title "A song about the walking dead" is something I would be a lot more cautious about, really smells of over optimization. I mean, you already said it in the first part of the title!
I would remove the following tags, and replace them with something more appropriate:
let's play the walking dead, clementine and lee tribute, the walking dead game soundtrack, telltale games, clementine, lee,
Since you don't mention clementine and lee in the title, I would use better tags instead.
Lets play and soundtrack isn't actually what the video is about, so again, I would use more appropriate tags.
telltale games is a "wasted" tag - you're not going to rank for it, just by having that one tag randomly in there, so might as well replace it with something better.
If you wish to keep clementine and lee in there (your song might actually be about them), then I would make sure to include that in your title, like:
"The Walking Dead Game Tribute Song | ORIGINAL TRIBUTE SONG | Clementine and Lee Love Song" (or whatever, haven't played the game).
But personally, I would centre more about what keyword you want to go for:
Clementine and Lee? The Walking Dead? Tribute Song? Walking Dead Tribute Song?
I jumped into the Google Keyword Tool, just to get a rough idea of what is being searched for, and the only one that's really worth it, is "the walking dead song", so I would suggest you focus on that one, for the most views.
Last, checking your own videos rankings, aren't reliable. YouTube search is fairly personalized, so it's likely you won't see the same result others are seeing.