Sounds like you are really talking about borders. If so, the reason they are wonky is probably because you just added strips to the sides by laying the border fabric to each side. The way to stop that is:
1. Measure both the horizontal and vertical sides in the middle and at both edges
2. Take the shortest measurement for horizontal and vertical and cut the border strips to the size.
3. Sew on to the edges easing in the border to fit
4. If you are adding 2 borders, make the 2 strips a unit and then attach as one border, each the same length.
Hopefully I've explained clearly....By the way, if your quilt top (before borders) measurements are way off you need to square the quilt top before starting this procedure of adding borders. You can ease in up around 1/2 - 3/4 an inch easily but if it's inches off this won't work.