You will have an Xtransceiver call with Cheren and Professor Juniper after the battle. There is an X Accuracy to the west, which increases a Pokemon's accuracy for one battle. North of the X Accuracy is a house where you can heal your Pokemon. Keep heading west from the house, through the rocks, until you see some stairs. Walk down the stairs and there are two Fishermen to battle.
There is a house to the west. Inside is a Worker that will give you TM 28, Dig. With Dig, the Pokemon burrows under the ground where it can't be hit by most attacks on the first turn, and then Dig hits on the second turn. Dig can also be used outisde of battle to transport you to the beginning of a cave or dungeon like an Escape Rope. There is also a vending machine near the house if you need to stock up on anything. Walk north to the Desert Resort.