I personally suggest using a big marker (like a sharpie or something) to pen in your Stats, name, etc. and assets (excepting anything you'd need to erase and rewrite, like HP, which of course you'd need to use a pencil for that if you prefer it to be on your sheet.)
I like to color in the icons for the stats according to if the value of that stat is good or not (you can make poor Stats red and high Stats yellow or blue or green, or whatever.) Colored pencil or highlighters or crayons are all good for that!