Use CA glue with the spray acelerator. Holds fast and you can apply the strip right away. $10 - $15 for both at a hobby store

To cut the the scarf; place the strips parallel to eachother with a slight overlap and cut thru both at the same time.  This will result in the angles on each strip being the same. Make sue you have enough length on each end so you can trim to fitl

JM

I made a miter box of plywood especially for the scarf joints. As JM says, overlap the pieces, and cut through both at once. Use a sharp, fine-toothed saw, and cut as squarely as possible. I used thickened epoxy on the shear clamps, and titebond wood glue for the strips. For clamping, I usually use four small C clamps-two clamping the glue joint together, and two aligning the strips flat.