I used pieces of paper to gain rough measurements for my troll character and transferred them onto an old t-shirt that I then cut up and stitched together. The whole process was very hit and miss, but luckily the clothing didn't need to look well finished for the job I needed it for.
To get around having to deal with making a neck for the clothing, I took the troll's head off, poked the armature through a small hole I made in the material and then reattached the head.
Rather than go through a more complicated process for the skirt, I simply wrapped pieces of burlap around the model, stitched it in place and trimmed it off with some scissors. I did a similar process when making the head scarf. I'm so glad that the character is female, and the style required is forgiving to my tailoring skills.