Keep it simple. Your kid is turning one and most likely will not remember this affair. We had a very simple party in the neighborood park. I mdae it special by baking a cake in the shape of Bella's favorite stuffed animal. I made her a ring of flowers to wear on her head. We had some food and drink, candy and cookies. The kids played on the jungle gym and swings, blew bubbles and ran around (for those who were able to...Bella was still not walking!).
There's plenty of time to get more elaborate. This one is more for you and the adults to celebrate your child!
Happy Birthday and good luck!