Rules for labeling? Every map has their own needs regarding labels. Some labels I place inside a banner, so just sit as text on the page. I tend to do black or white (with halo shadow) depending on whether the map is background is dark or light. While I might use a Celtic font, I try to use fonts that are readable (many fonts aren't suitable to labels being too fancy and difficult to read). I will sometimes use a different and different scale for a regional label versus a city label. I will often choose a different font for the main map title. I don't have one set of label rules, as stated each map has it's own requirements. Another consideration is sometimes I use a Celtic style font for a European-based map, I'll use something else for Asian, Egyptian, Viking - I try to use fonts that match the culture of the map area, but nothing too fancy, nor unreadable.