We just had DD's first b-day party last month and it was HUGE. We both have large families so our house was bursting.
We didn't do goody bags. There were only three other children present and one was an infant, so I didn't bother. Next year however I probably will do something for the older kids. A pinata maybe. This year there were just too many people and the place was too packed.
My biggest bit of advice would be to make sure the timing of the party takes into account nap times. We set DD's for right after her morning nap. Which would've been perfect had she decided to take a nap that morning.
She did really well anyway, but she has red rimmed eyes in all of her pics from that day.
My other piece of advice is to accept any offers of help you get. From cooking to cleaning, just say yes to everyone.