I wanted wood shake shingle for my buildings, but have never found what I was looking for in premade forms. Usually they come in premade all the same color/peel-n-stick/never enough sheets. They didn't look real enough for me. Browsing the local home improvement mega store I saw this product. I was available in Oak or Birch. Birch is too hard and smooth to take the stains readily and did not have the rough cut shake look I wanted. The Oak fit the task best. After trying different method the below is what I found works for me. These technique is used on my ON30 layout and the size of the veneer may not lend itself to the HO scale.
The veneer comes in rolls with a hot glue on one side. I started with wood glue at first, which then took too long to dry and the shingles moved around if I did not let them set up. I have a heat gun, not a hair drier, which gets hot enough to cause the veneer to burn if you heat it too long. I use modeling tweezers, hold the venner for just a few seconds in the heat stream and the glue melts enough to them place it where you want it to go. Press in down and the shingles are permanently "nailed" down.
I started cutting them with scissors - no good. Tried the handy wood cutter by NWSL - no good. Tried the X-acto blade - better, but too smooth an edge. I mark on my cutting area two lines the length I want the shingles to be, lay the veneer upside down(glue up), place the X-acto tool on the veneer and rip upwards on the veneer and tear the shingle. This gives a ragged edge and the shake shingle look.
Now if you want to, and this takes a long time, cut individual shingles in varying widths and then place each one on. Great for small areas and the ends of roofs and such. If you need a lot of shingles I use the veneer cut to width and cut 3-4 notches to simulate individual shingles. This makes the application goes faster. Vary the width of the cuts and the look of the shingles is improved. Draw lines on your roof base or if you use individual boards, make sure they are straight. If you want to cover the shingles joint below each row, your choice. I just put the shingles on, and because of the varied widths of cuts, they seem to cover the joints and look good after all is done.
I stain the Oak veneer with Alcohol and Ink stain, I find a color I like and then go for it. I put on a wash of brown shoe dye and alcohol first then go over it with a black dye A&I stain. One tool I use constantly in all my modeling is an old hair dryer. I am always drying each piece of work before going on to the next item.
This is a lot of work and I take many coffee breaks in between, but the effort is worth it.