VGC - Format Rules - 6 Pokemon - 4 Fielded
HIGH FREQUENCEY MECHANICS - Things you will see a lot in Doubles:
100% Flinch Chance locks an opposing Pokemon down and deals damage. If you are relying on a set up or want to counter the opponents' this move does both.
I usually have a back up plan or Ghost type [IMMUNE] if they are packing a Fake Out user.
Attacking and switching can be a powerful way to keep pressure on, momentum up, and your opponent guessing while you fight for a better position.
Weather and Terrain are most commonly seen being triggered off of abilities but sometimes trainers use moves to generate these effects as well. Many teams are based around the unique status/buffs/pressure created while they operate under these conditions. even if you aren't a focused weather team it might be good to pack an effect just to nullify theirs however with the advent of Dynamax moves changing weather it might be less relevant.
Taunt prevents the use of Protect and other annoying moves [SPORE]. Many teams rely on tricksy moves to gain an advantageuos position and Taunt shuts them down- especially harasser builds that sometimes carry no actual attacks and end up using struggle if your taunt goes off before their status move.
Protect - Status Move
While Protect at times will see play in Singles formats as a useful scouting and stalling tool in Doubles nearly every mon on your team should have this (exceptions for niche team members playing a role). The reasons are many- read that the opponent wants to send two attack at one mon? Protect with it and attack with yours and you got a free turn! Grassy Terrain is active? Time to heal up and stall their Wood-Hammer guy.
There are many many combinations of pokemon that can work in Doubles- one of the most powerful are mons that "Combo" with moves and abilities. A prime example would be Levitate Weezing using Sludge Wave to hit the whole field while Steelix Earthquakes- Both attacks hit every mon on the field but will miss the partner due to typing immunities and in Weezings case its' ability Levitate grants this immunity. This can wipe some teams right out of the gates.
This move was made for multi-formats like Doubles- You will never see it in singles barring an accident because it serves no function on it's own. In Doubles it allows weak attackers to add offensive value by powering up the targets move by 50%. I have OHKO'ed my opponents starters with a Helping Handed Normal Gem Boosted Explosion but really that's just a dream scenario.
Statuses can really shut down a mon so you will see them on nearly every team in some way; Thunder Wave, Will-O-Wisp, and Spore are the best ways to administer Paralysis, Burn, and Sleep respectively. Each is crippling in it's own way- use the one that covers your weakness or supports your team the best!
Moves with a speed priority like Quick Attack are great for finishing off weakened or glass cannon mons- some mons have such high attack stats that these are as dangerous as regular moves. Sucker Punch and Extreme Speed are Kings of priority damage but with Stab, type weakness, and abilities like Technician to power them up the smaller moves see a lot of play as well.