Trace or copy your patterns and tape them to cake board(s). Cover the board securely with wax paper.
When outlining, if the edges are not smooth you can use a damp paintbrush to touch it up or a toothpick to nudge the outline into place a little.
To tell if the consistency is right to fill in, drop a bit from the spatula into your bowl and it should lay flat in about 10 seconds. Add water sparingly.
When you fill in the thinned color flow, it should puff up in the middle but not overflow.
Make sure that the piece is dry. You should make several test puddle. Use them to see if your piece is dry before removing the actual pieces.
Lastly, if you are making something that needs assembly (such as the cake I made below) or if you think your piece might fall off your cake due to placement, you will need to make extra pieces in case of breakage. 
Good luck and have fun at it!
I'm sorry that I have to be the dumb one, but what do you use for color flow? is it royal icing?
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