Well you can try eBay and get that 'nismo' body kit which is pretty cool, would give you a link bu I can't find it, somewhere here might have the link.
If your Micra isn't an SR/Super S/Si or any other model with the spoiler, get a spoiler or the micra sport body kit with the fog lights, they're more beefy and sexy.
Put some led lights in your dash to make it look cooler.
get a decent sound system!