Jean genie

It takes two: Years ago we could have one perfect pair of jeans to do everything, but now you need a few different styles. My staples are boyfriends and skinnies. The skinny has become a perma-trend - it looks good with heels and flats or tucked into boots. A trouser style in dark denim is a smart look for work, a classic boot-cut is almost universally flattering as it elongates the leg, and a cropped jean - just above the ankle - is a great mid-season look.

Dress to your shape: A body shape I see a lot across all ages is one with no defined waist and slim legs, which looks really good in a high-waisted, straight-leg cut - it tucks everything in and gives a nice line. A boot-cut looks good on everyone because of the way it flares out slightly from the knee - it makes thighs look slimmer, legs longer and tends to make people stand up straighter. Skinny jeans are perfect for slim, boyish figures. Pear and curvy shapes need something slightly high-waisted for their small waists in a dark-wash, straight-leg or boot-cut. Back-pocket details give flat bottoms a boost, whereas large plain pockets play down bigger bottoms.

Help is at hand: It can be overwhelming when faced with a wall of denim in a shop, so ask for help. If you want jeans to go with a particular high heel, take the shoes with you so the hem can be pinned there and then. It's useful to have some idea of what you want, but go with an open mind and be willing to try different styles.

Think colour: Dark blue and black denim are safe, flattering colours to invest in. Pale blue can be tricky. White is actually much easier, as is grey, which can be paired with strong jewel colours.

The shape of things to come: The boyfriend jean is really coming into its own and will carry through into next season. It's so comfortable and is mostly worn rolled up at the bottom, but also looks great worn long with a heel. You can really play with the shape. Denim leggings - or "jeggings" - are fantastic and surprisingly flattering.

Just say no: Avoid trends if they make you feel uncomfortable. Ripped jeans are popular, so if you're a neat type of girl they might not be for you.

Embrace the muffin-top: It doesn't matter how thin you are, everyone has a muffin-top in jeans. They have to grip on to something. And you should have it, because you need to buy your jeans really tight. Once the denim eases up a bit, it won't be so obvious.

Donna Thornton is the founder of the London denim boutique Donna Ida.