The most important thing about making a patterned shingle design is that your design MUST be in the middle of your roof. It can not be off. Even the slightest little off margin on your first row of shingles, will cause your pattern to be off center so please, make sure your first row of shingles is centered. Centered means that the last shingles on each edge must be cut exactly the same. In other words, you can not begin with one whole shingle on one edge. They must be exactly the same. These are cut in half. As you can see each end shingle on the first row is cut in the half the same way.
I am using a combination of hexagon shaped laser cut shingle strips, which I stained a little darker than their natural color and loose birch veneer shingles, which I cut to a hexagon shape. The tutorial I followed is here. This tutorial is exclusively for the shingle strips but if you have loose shingles and you would also like to make a patterned roof, then you can follow this tutorial here.
I applied the first row of shingles upside down so that it's a nice straight line across the bottom edge of the roof.
I am going to try and avoid using corner trim on this roof but I can not guarantee I won't have to. It all depends on how straight I can get my angle cuts so I can butt the corner shingles together tightly. Sometimes your shingles will cooperate and cut smoothly and other times they will not. It all depends on how brittle the wood they used for you particular batch of shingles is. So, there is always a possibility that corner trim will have to be used. For a stained shingle roof like this, you will want to stain your corner trim in order to have it blend with the rest of the stained shingles.
It's best to make your design right on your dollhouse roof. I don't recommend using template for this style roof. The template does not let you see who the design is actually coming out on the actual roof and you might make a shingled template that could be slightly off center in the end or not completely straight.