Birthday banners can be made or bought. We did both and scattered them around the house, both inside and out.
The preschooler and I cut strips of colored paper with the shaped scissors and attached a balloon. I got my husband to help with the ladder to stick them to the ceiling every 3ft or so, it looked much nicer than appears in the below shot. For some reason my high/ceiling shots don't come out as well (maybe no focal point?).
Also while he was sleeping the night before his birthday we blew up balloons and scattered them all over his room, so he woke up with a nice surprise. I didn't take too many pics but I think you get the picture.
Also we hung streamers all over his bedroom door, so he walked through a streamer curtain when he got out of the room, also missing that image.
Party or not there must be cake and we usually order one from our local supermarket bakery or you can make it yourself.
On the day he got to choose all meals, including where he wanted to eat and what he wanted to do. Minimal rules and he got to eat candy between meals etc. Something to differentiate the day from the usual day to day. Make sure you tell the restaurant that you are celebrating a restaurant for a round of Happy Birthday.
We bought a 'Its my birthday button' and made him wear it on the day. So anyone he would meet would wish him a happy birthday. Or you could make a birthday hat. We also got a birthday pre recorded message for our birthday boy too. One other idea we never got to is to write a birthday letter to your child, perhaps next year.
Happy Birthday Stephen!
May your future birthday planning be easy and fun too!
XO