The town is has the Lavaridge Town Gym. Flannery is the current gym leader and specializes in Fire-type Pokemon. Make sure to have your appropriate Pokemon ready. Before going there, you can check out the town to find more items. Outside the Pokemon Mart, you'll find a martial artist. Answer "No" to his question to receive a TM75 Swords Dance.
There's a woman in the Pokemon Center that sells Moomoo Milk. This is a cheap, recovery item that you must have in your inventory. The Pokemon Center has two entrances leading to the hot sprint behind it. Enter the pink entrance and find the hidden Ice Heal in the water using your Dowsing Machine.
If you head west from the Pokemon Center, you'll find an old woman that will give you an Egg that you can hatch. To receive this, you should have at least one free slot in your party.
Beside the Town Gym are two houses. The one to the right has a Zigzagoon that you can scan for your DexNav. Beside it is the Herb Shop. Talk to the old man in front of the counter to receive a Charcoal.