Need help doing a flame border for Transformers cake due tomorrow. Any tips/ideas will be appreciated.

you can put red, orange, and yellow icing in the same bag and use a star tip.

if you're using fondant, you can start out with white and then paint a coat of yellow, then some orange, and then some red.

i use the leaf tip for flames

yeah...a leaf tip will work too...forgot about that one!

Both of those are great ideas - just use whichever one you're most comfortable with and good luck!