Make sure you read Waterkeeper's build log, lots of step by step pictures.
I have a build log running right now too, but I'm making mine out of wood, so it wont be exactly the same. What kind of critter are you keeping/planning to keep? I am building mine for frogs, and I think the frog landings are a pretty original idea (I could be wrong) but you can feel free to look and ask any questions that you think I can answer.
Welcome to the forum.