I'd put it away until I felt I had enough experience to do it. When I first started doing half square triangles I always made them about 1/2" bigger than they were suppose to be. That way I could trim them up and make them the right size. Even then I had some that would not trim up.
Now I just use my GO cutter. It cuts them perfectly, and they go together perfectly, and it puts me in a real good mood!