If you know you will have to finish a garment's raw edges, it is easier to cut out the pieces with straight scissors.  If using a zigzag finish, do this before constructing the garment.  The same applies to using a serger to finish the raw edges - a 3-thread overlock is sufficient.  For a lighter fabric, you can turn each raw edge 1/4" to the wrong side after sewing a seam and stitch with a short stitch close to the fold.  For heavier fabrics, refer to my discussion on the Hong Kong finish.