There is something to be said for simplicity. Up until now, I've always decorated detailed and over the top cakes for my kiddos. But when my brother gave me free range on my niece's 1st birthday cake with the only direction of "teal", I went for a little simplicity.
I use and recommend Wilton's Snow White Buttercream Icing recipe and the Wilton #104 Decorating Tip. Other tips in that family would work as well.
The icing technique I used as reference can be found in this video by Rose Atwater.
The finished product looks difficult, but it's really quite simple. The only pointers I would give, make enough icing. I made 3 batches, and color matching is NOT fun. The other tip... allow time for your hand to rest. Between sifting cups of powdered sugar and putting pressure on the icing bag, my hands were DONE.
The adorable bunting fabric is City Block by Kitty Yoshida for Benartex
2. Chalk on or draw a triangle, with the largest end on the crease of the fold
3. Cut out your triangle, cutting through both layers of fabric.
4. Your end result is a diamond that you'll wrap around your ribbon or string and sew.You'll also need wooden skewers, these are commonly used for BBQ and are safe to put in the cake. I'd caution you not to use anything not made for food. I used fabric markers to write her name, but alphabet stamps could work also.