If you have a pear shape, always go for jeans without too much detail, embellishments, or flaps on the pockets. Buy jeans with midsize pockets that are not too far apart. Also, a mid-rise is preferred as a high waist could make a larger midsection look bulgy, whereas low-rise may give you plumber's crack. Great affordable designer jeans for a pear shape are Joe's Jeans - The Honey, James Cured by Seun jeans, and most AG jean cuts. If you are short, a straight leg looks best as boot cut can often make you look stumpier or flood your legs. If you are tall, a boot cut can balance out your hips.
Try zafu.com. This web site helps find jeans that will fit your body type. You answer a series of questions and receive the names of different designers/makers based on your answers. Hope this helps you find that perfect pair.
Try Next for jeans, I have found some really nice fitting jeans there recently. I found BHS jeans gaped too much at the back of the waist and Evans were too baggy on the hips. M&S were disappointing but I have had some good fitting ones from there before.
Gap. They have a wide selection of jeans in all sorts of styles, lengths and colours and (some) knowledgeable staff. I took my mum there for jeans (she's in her 60s and a little reluctant ) and she loves her new "low rise and curvy" jeans. My husband got "lean and long". And they're not a bad price.