The best moveset for Tsareena in the current competitive meta typically features the moves Triple Axel, Trop Kick, Protect, Low Kick.
In the Pokémon Champions meta, Tsareena can be countered by exploiting its weaknesses (bug 2x, fire 2x, flying 2x, ice 2x, poison 2x) and using effective check/counter teams.
The best item for Tsareena is typically Sitrus Berry, based on high-level tournament and ladder stats.