You can try completing certain quests or participating in specific events related to it. Sometimes, rare drops from monsters might also give you a chance to obtain it.
One good order could be starting with the Tutorial Island quests as they introduce the basic mechanics. Then move on to the Lumbridge quests which are relatively easy and build a foundation. After that, quests like the Vampire Slayer quest can be a good next step as it has an interesting story and unlocks some useful items and areas.
It's hard to say for sure. 'Tar' could be a completely fictional creation or it might draw inspiration from real-life situations and then be embellished.
Well, it could be. But often, even if inspired by real life, movies or books might tweak things for dramatic effect or to make the story more engaging. We'd need more info on 'Tar' to know for certain.
Tar fiction is not a commonly known term. Maybe it refers to some fictional works related to tar or something made up using the word 'tar' in a creative context. I'm not really sure though.