Before you read this you will need to read my instructable on how to make a Altoids tin replica.
Heres the link.
My replica of an Altoids tin completed
Step 1: Modifying
First the paper clip and tin need to be "modified"
Use pliers to stretch out the paper clip.
The use scissors to cut of the side marked in the picture.
Also drill a hole where the little image note tell you.
Step 2: Making the Hinge
To put the hinge on, cut the paper clip a few millimeters more than the side you cut off.
The put it through the 2 holes you drilled.
Now solder on the lid tho the paper clip ends.