Okay then, this analysis needs bulking up yes? Well then, I'll add some things that need to be mentioned.
Rock Polish set
-Mention paralysis support, as before a boost, Torerra is slow and it doesn't outspeed very much.
-Mention entry hazard support to wear down switch ins. Surprisingly, Torterra forces a lof of switches, and Toxic Spikes help wear down bulkier opponents such as Cofagrigus.
-Mention some special attackers, Pokemon that can break through physical walls, Taunters, Toxic Spikes, and wall breakers
Choice band set
-Mention Pokemon that can switch into Ice-type moves, Torerra is slow, and dead if it gets hit. Mention Water-, Ice-, and Steel-types, and Thick Fat users.
-Mention entry hazards to weaken switch ins
-Mention a cleric just in case Torterra gets burned. Flash Fire Pokemon can switch into Will-O-Wisp and Water Absorbers can switch into Scald.
-Again, paralysis helps overcome its Speed
-Torterra is slow, use a special based revenge killer to beat fast threats, and to beat special walls.
Offensive tank set
-Torterra can't take Ice-type attacks! Remember? Use Water-types, Clefable, Fire-types, Thick Fat Pokemon
-Mention Wish support if you decide to use Substitute in the last slot
-Paralysis support is always helpful
-Entry hazards are good, especially Toxic Spikes along with Substitute
-Mention Leech Seed and Substitute in AC, say they can be used together
Swords Dance set
-Ice-types!!! Pokemon that can beat them are vital. Mention Fighting- and Rock-types that can hit them super effectively
-Mention paralysis support, again
-Entry hazards are helpful, as usual
-Special attackers can break through physical walls. Use Taunt and wall breakers too. Perish Song deserves a mention too.
Defensive tank set
-This DEFINITELY needs Pokemon that can switch into Torterra's weaknesses. Think of its Fire-, Flying-, Ice-type weaknesses, and think of Pokemon that can switch into them.
-Mention a spinblocker that can keep Stealth Rock around. Mention Roar as well, as Torterra is a decent phazer.
-Toxic Spikes help it wear down bulkyer Pokemon in the tier, such as Musharna and Eviolite Dusclops and the like. Cofagrigus, many more.
-Mention that special attackers are needed to get past Weezing and Tangrowth.
SubSeed set
-Mention Pokemon that can defeat Torterra's weaknesses, or more specifically, switch into them. Flash Fire users, Thick Fat users, Water-types, there are tons of options.
-Mention that Grass-types, such as Tangrowth and Ferroseed, cause problems for this set. Use Fire-, Ice-, Flying-types to beat them
-Toxic Spikes are an excellent way to wear down bulky Pokemon like Tangrowth, and work great with Substitute and Leech Seed
Curse set
-ALWAYS, ALWAYS, ALWAYS, have Pokemon that can switch into a Curser's weaknesses
-Mention a cleric or status absorber. Torterra is screwed if it gets poisoned or burned. Heal Bell, Aromatherapy, RestTalkers, and Natural Cure Pokemon are good. And Hydration Accelgor works too.
-Toxic Spikes are always helpful, consider them to weaken the opposing team.
-Paralysis/sleep support is helpful. Torterra appreciates the help setting up. Consider Encore users that can lock a Pokemon into Electric-type attacks as well
NOTES
-You need to give specific examples, and explain why each Pokemon is good. Try and use different examples for each set, and be creative, but not stupid.