I'm very experienced with making fondant cakes but don't feel comfortable doing all buttercream cakes at all. I have an order this weekend for a 3 tier buttercream cake with fresh flowers and would really appreciate some tips. I think my biggest worry is that the buttercream will soften and start sliding since it is pretty warm right now where I live. I plan to substitute some of the butter with shortening (not all).. any other tips? Also, what is the best way to insert fresh flowers into buttercream? No advice is too small.. thanks in advance!

For me, I just don't do buttercream cakes for outside events (I'm assuming it's an outside event, since this is a concern).  With that being said, I've heard that indydebs buttercream holds up pretty well.