Im having a Birthday Party for my dog's 1st Birthday, any suggestions?

My baby girl(yellow lab) is turning one soon and i'm planning a Birthday Party for her (is this weird??) in my back yard, which is a decent size. So far what I have is her b-day girl outfit, cake I got from a local pet bakery and decorations (Princess Theme). I have never done this before so what else do I do? like what do I feed the doggies? what about games? how many dogs(friendly) do I invite? How long should it last? Also how about just making a barbecue out side like burgers for the parents would that be ok? I would really appreciate any suggestions you might have Thanks :)