Hey, I would say that when playing as Predator there are multiple approaches depending on the skill level of the fireteam. I find what works best for me and how I enjoy playing the most is hit and run long range tactics from above with the occasional ambush if and when the fireteam splits up a bit. n most cases I often use traps from above and the plasma caster when they are caught, then when downed ill drop another bear trap in their area and wait for their teammate to revive them. If they crawl out of the range of the bear trap Ill finish them off. Ill ambush periodically with the combistick and Net to switch up the tactics on the Fireteam and keep my movements unpredictable.
If I'm in a situation against a good fireteam that work together and are aggressive, ill bait them into chasing me on foot and while running away ill drop a trap or two and when they run into it, ill get up in a tree and ambush them that way. Against good fireteams you have to be very quick and keep your movements unpredictable.
A lot of Predator players use some of the, in my opinion, easier approaches like playing as Bionic, spamming the plasma pistol or Alpha Predator and or tanks like Scar all with the Alpha Sickle, but I find that they are to easy to use and not as fun. I use Elder Predator and Captured Hunter to get as close as I can to Jungle Hunter since he's locked for Xbox players.
For fireteam, its pretty straight forward but I will say working as a team is the most important tactic. Everything else is second to that in my opinion. Also, get good with the knife, it'll keep you alive a bit longer if a Predator is very aggressive. In terms of weapons, a lot of players use sniper rifles and explosives, I prefer the Assault Rifle, Hammerhead.
Hope that helped.
My GT is BKLYN CANNON if you want to team up, feel free to add me.