Turf Takeover is a game mode in Plants vs. Zombies: Garden Warfare 2. According to this mode's description, it is a mix between Gardens & Graveyards and Herbal Assault. The mode can play one of 5 maps, and it can switch from Gardens & Graveyards to Herbal Assault.
Because the maps are randomized, you will have to memorize which maps have the plants or zombies attacking or defending. Once you do this, you can switch to the team you like best, either on the offense or defense. As for the mode itself, apply the same strategies as you would for the modes.