>>17718250welcome to the wonderful world of doubles OP.
i would recomend lead with something taht can fake out, that buys time for a slower pokemon to set up or do another thing, i usually lead with mega medicham/empoleon, i fake out the fastest pokemon then i icy wind with empoleon so i can cripple the other pokemon speed, you will see a lot of shitty strategies like mat block greninja on battle spot or whimsicott/terrakion, victini/spinda on showdown but when you learn to counter them their "strategy" falls appart and then it will be easy for you, make sure to pack pokemon with moves that can hit both targets, trick room abomasnow rapes shit there let me tell you, and keep on eye on crazy japs with cresselias.
good luck