Almost everyone needs jeans at some point: a casual pair to go to the market with your grandma, or a smart pair to take someone out on a date. So if you can only bear being in a shop long enough to buy one pair, pick one that you can dress up or down, and that fits brilliantly.
There are three basics to remember about jeans: cut, fit and wash.
1. The cut is the shape of the jeans, for example, bootcut, skinny, straight leg or high/low rise. Different cuts work best on certain body types which is why trying them on is crucial.
2. The fit is how the jeans sit on your body. Common fits are slim, regular and relaxed. The right fit/cut combo can make you a demi-god. The wrong one just won't.
One thing that most guys don't consider is how a pair of jeans looks from behind. You want them to look good in the bum, but this doesn't mean swamping your buttocks in excessive amounts of fabric or having jeans glued to your glutes and inhaled by your buttcrack.
a. If you're particularly slim, you may be surprised to know you should go for slim-fit, not baggy jeans. Loose-cut jeans swamp you, and make you look even skinnier than you are. Your best bets are skinnies and bootcut, which are very slightly flared at the bottom and fill out your rear. In a good way.
b. If you have a slim or athletic build, try bootcut, or straight leg; they're snug enough to flatter your lower half, but not so much so that you look like you squeezed yourself into your clothes.
c. If you have a bigger build, try a relaxed fit, with wide legs; but again, not too baggy, as that makes you look bigger.
Whatever your build, do not wear jeans that give you a "builder's bum" (when your bottom shows between your jeans and top) or that hang down around your knees: you're not a 90s rapper.
You must also make sure your jeans are long enough. The back of the leg should come at least to the top of the sole of your shoe. You don't want to flash your socks; but neither should the cuffs drag on the ground.
3. The wash is the colour and "effect". For example, dark, distressed or stone-washed. Certain washes work for every occasion (dark is perfect for everything from hanging out with the guys to pairing with a blazer for a semi-formal event); some, like "classic blue jeans", are simple and casual, while others make a statement. Take stone wash: it screams 80s, but if you're confident, go crazy and rock this throwback.
Now, offer to buy coffee for a good gal pal or your mum (we're better at shopping) if they promise to get you through the ordeal in an hour or less, then man up and hit the stores.
PS: Once you've found a pair of jeans that look and feel great, if you can afford it, buy a second pair (or note the brand and model so you can buy another pair later). And take care of them. Wash them inside out, in cold water and dry them flat.