Your rule for changing thumbnail and title

Hey guys I just uploaded a video thinking it was the best thing and surprise it did bad so what are your guys’ rules that u follow about when to change the thumbnail and title for your own videos. My video got around 15k impressions really fast but only around 150 views and now it’s just stopped. So would really appreciate any advice on this thanks and also do u think the thumbnail and title change would even work in this scenario or was the idea just bad?