The paper is the most important componant if you wish to color your sketch : an unsuited paper will quite likely wrinkle or tear during the coloring.

That's why I use Layout or thick paper for printers (110g/m²). The Layout has a layer that prevents from soaking with markers ink. As a result, a density of 70g/m² is enough for this kind of paper.

Warning !
Layout is not usable on both sides : draw on the front side only ! Inks don't fix very well on the verso and you may smudge !

I usually work with Letraset® Tria™ markers. These pens have three different nibs : a fine nib, a broad chisel nib and a brush one. They are durable and refillable. (one refill can be used about ten times).

Unfortunately, these markers and refills are not marketed anymore. They were replaced by a new model less efficient. This new version also has three different nibs, but inks wear out very quickly. For example, I never used the brown marker as shown in the picture. Yet it worked three weeks before, when I purchased it. Furthermore, refills don't exist anymore ; there are only cartridges that are more expensive.

The best compromise seems to be Promarker pens, also by Letraset©. These markers have only two nibs and the color chart is much more limited than the Tria™ markers's one. Nevertheless they are durable and cheaper than Tria™ markers.