So I am going to talk a bit about inking. Not sure if that is an accurate translation from Japanese (sumi-ire) but it will do for now. Whether you decide to ink or not is up to you but if you want you Gundam to look cool, mean and groovesome rather than wet n wimpy then whip out your Gundam marker and follow me...
Top Left: This is the back of Gundams head - has been given a coat of spray but as it stands Gundam is at risk from being called a wimp just by the appearance of the back of his head.
Top Right: Go to your nearest modeling store and grab yourself some Gundam markers (and don't forget to pay for them). Then draw along the grooves on the helmet. If you are inking on a white surface, grey, purple or brown is recommended as the color to use. Do this when you are at home and not on the train as you will have ink going over the edges - you will probably get strange looks and maybe even arrested for being a nuisance in public.
Bottom Left/middle: Now this may not be common knowledge, but you can use a pencil rubber to clean up after inking. I didn't know this when I started modeling and used thinner to rub out excess ink which was bad because I ended up melting a few parts by laying on too much thinner. You can use some fine sand paper to get into the nooks and crannies to remove excess ink too.
Bottom Right: And this is the finished product - nobody would dare to call this Gundam a wimp.