And this is the process and the result.
(Sorry by my English... I hope that you understand the steps).
Step 1: Search the side face
I selected this dinosaur because it is very easy to recognize by the kids... and it looks not as complex as a T-Rex with a lot of teeths :-)
Expand the best view until the desired size.
I downladed other Triceratops views to get more details and complete the skull on last steps.
Step 2: Building the base for the skull
Both sides will be the base for our skull. You have to join them and hold with tape.
Step 3: Complete the base for the skull
Step 4: A few details to look better
And I hold all pieces with tape.