first you must analyze your video type.
if its a tutorial, or how to or like this, it can be long as 10-20mins
But if its another content you can limit the video avarage 5-10 mins.
People get bored some long videos.
Tip : If you share any tip in your video, you can share this tip through the...
Right point. But your subscriber type = your channel niche
If u have a niche channel you will get subscibers who are related to this niche.
If u have a global channel. You can get all kind of subsciber:)
I gues tubebuddy pulls data from Google Adwords for related keywords and search volume. But it takes and searches it in English language.
As we know google has many domain extensions for country based search results. So in Turkey im using .tr entension and if my keyword is in Turkish...