You can quickly make your own outline patterns from existing assembled wood parts with just a piece of white paper and an awl. Position the paper over the piece you want to duplicate and then rub around the edges. Remove the paper and lay it over your new wood. Next, following the creases, punch small holes into the wood with the awl. For straight lines, a hole at each end is sufficient. On curves, make holes closer together. Remove the paper, draw lines between the holes, and you are ready to cut.
You can square up a wall before raising it by measuring from opposite corners. Assuming that both the top and bottom plates are equal in length, and that both ends are the same, the wall is square when the diagonal measurements are equal. Adjust the wall as necessary, then keep it square with sheathing or with diagonal braces before raising it.