As an Arsonist my strat is to actually play the part of a Bodyguard, douse the Jailor twice and get confirmed as a TP by a Lookout, then you start 'Protecting' the Lookout
I also like to leave an Investigator alive because they will be getting a lot of BG, GF, Arso results that can be lynched in my place before finally pointing out how funny it is that everyone the Investigator visits just happens to be doused
These are a couple of on-the-fly strategies to use for the greatest role in the game Arsonist