Probably the most important thing you can do after putting together a model is give it a pose. Add some life and personality to your kit.
It's a rookie mistake, your Gundam shouldn’t stand around stiff as a robot. It should be allowed to loosen up as to look and feel more natural.
(click for larger, via ??? with thanks to /m/)
From here on everything is up to you. Reenact a scene, pit it in combat against another model, make it dance, facepalm, etc. If you’re working on your first kit with individual fingers, do what everyone does the first time, flip the bird. I really shouldn’t have to help with this part.