If you want something that feels like a precursor to comp, try playing the common comp setups when they're double points in red hearts. Most players (including myself) take them a little more seriously than your usual red heart games because of the extra point incentive to win.
At the same time if the table is generally pretty bad I wouldn't expect a quality game. A table is usually only about as good overall as its worst two or three people, so if you can't fill it with strong players then it'll be hard to get a really good "competitive" experience.
The best way to prepare for competitive is simply to dive in. The way red heart games, such as FP, are played, is starkly different from competitive as the setups are more complex and players typically use more in depth strategy.
I would recommend reviewing some games of gold hearts (you can simply search for completed gold heart games and read through the game logs in main lobby). Once you have an understanding of the setup mechs and how different roles work, definitely recommend just diving right into it.
