Keep it short -- about two hours. Little kids can't keep it together for more than that.
Don't make yourself nuts baking, decorating, and hand-making everything. It's a big event for you, but it's not like your child is going to have a clue what's happening. So do the one or two things you enjoy and are good at, and farm out the rest.
Pay your nanny or favorite babysitter to be on hand -- her familiar face may help comfort your baby if she's overwhelmed by all the family and friends.
Don't bother with elaborate games or activities. These are 1-year-olds we're talking about. Approach it like a big play date instead.
Ask a friend to take photos or video the event so you can be in the pictures, too.
Set up two snack tables -- one with kid-friendly foods, like Goldfish crackers, and another that's higher up and out of reach with nibbles for the adults. Remember that some of the food you like can be a choking hazard for babies (carrots, popcorn, nuts, etc). I'd also like to add some foods aren't recommended for children until a certain age due to allergies, such as nuts. Keep that in mind!