without knowing the constraints you are trying to model how do we know whether your model is reasonable?

if you've looked at it for long enough
if you've read the suitable texts (Fundamentals of Relational Database Design -- r937.com and The Relational Data Model, Normalisation and effective Database Design) spring to mind
...and you've talked it through with your peers and your teachers / lecturers then its probably right or good enough

..unless you have got a specific problem, and can explain where your problem lies then I don't see how we can help with 3nf