There will be only one other ressonance structure. It will follow the second pattern, so a lone pair from the nitrogen will form a pi bond between the nitrogen and the carbon with positive formal charge.
Work Step by Step
1. Draw the lone pairs. 2. Find which pattern does that structure fits. It is the second one, a lone pair (from the nitrogen) next to a positive charge. 3. Draw the arrows: The second pattern says that, the lone pair from the atom next to the positive charge will form a pi bond between these two. So an arrow will come from the nitrogen to the bond between the nitrogen and the positive carbon. 4. Do the changes based on the arrows. * Don't forget the formal charges!