I use an old fashioned sewing seam gage. They have a sliding piece that you can move up and down the ruler, it works perfect for me. The only drawback is that they are only 6 inches long. I've never needed anything else, it is big enough. I use it to make sure my pictures, ribbon, titles ect are straight. You can buy them anywhere they sell sewing supplies. I would have to say, it's in my top 5 tools I must have to scrap.