If you have a straight, or rectangular body shape, you usually have little to no waist definition, flat hips and bottom, sometimes a short waist and very often long, slim legs. Here are a few tips to help:
1. Emphasise your legs - skinny jeans, leggings, straight skirts and coloured trousers are good.
2. Keep your midsection uncluttered by avoiding details at the waist such as belts.
3. Keep the lines of your clothing straight and choose vertical lines and geometric prints and checks if you like pattern.
4. Crisp and structured fabrics work well, such as cotton but if you have a large bust then wear slightly softer fabrics.
5. Avoid frills, gathers at the waist, fabric that is too floppy, and floral prints.
The above are some examples (from Boden) of what to wear if you have a straight body shape.