Since it her first birthday,it should be nice and memorable,so don't forget to make videos and taking pictures. As she will be one,you can buy gifts according to her needs like clothes,toys etc.
Choosing a place is up to you,either you want to do it at home or some hall or any restaurant,decorations are must. Since she's a baby girl,you can choose pink and purple color decorations.
For cake,it definitely has to be best,so order a nice cake for her also.
Its best to keep a first birthday low key and at the most and hour or two. It really isnt for the baby since at that age they have no clue whats going on, its more for the adults. Simple decorations, cake, ice cream, and a smash cake for the little one to dig into by herself. At one alot of noise and people can get them upset really fast and make them fussy, so keep it small and simple and take tons of pictures to remember it by.