In my first article on the new professional dress code, I’m going to talk about dressing for a techie job or event like a conference. The reason this topic is on my mind now is because my boyfriend is about to go to OSCON.

For those of you non-techie people reading, OSCON is an open source conference (geek alert) that runs from July 16-20 in Portland. And let’s be honest, if he weren’t going, I never would have heard of it, because I am not a techie. I am the furthest from techie that it is possible to be. I have, however, planned wardrobes for him for umpteen tech conferences, because he has absolutely no interest in clothes or style or shopping, although he does care enough to want to look good. I think of helping him as providing style for the unfashionable or the uninterested. And I think that at this point I have the right to call myself a techie fashion consultant, so listen up all of you techies, the people in the universe who are the LEAST likely to read a style blog. Just kidding, all of my stylish techie friends.

One of the perks of having a tech job is the casual dress code. More than any other field, technology has been influenced by the West Coast/Steve Jobs at Apple/start up casual culture. Dressing casually is now a virtue in the tech office. But despite the new casual ethos, all casual outfits are not created equal. Our clothes, casual or formal, still send signals. They are an indicator of how thoughtful we are and how well we follow social cues. Clothes allow us to look enough like our peers to blend in but can also let us stand a notch above them to get noticed. This post is for those tech office workers and OSCON attendees who want to do casual the right way, because they want to network or find a job or make a good impression every day. Being casual does not have to mean being unfashionable.

So, what to wear to your office or to OSCON? When a bunch of technologists get together, nobody is going to be wearing a suit. That’s a given. But what exactly will they be wearing? What should you wear if you want to fit in but stand out just enough to be noticed and still be yourself so you are comfortable? (Or the larger question, what is geek chic exactly?) And by the way, this post is not only for men. I am just going to talk about wardrobe basics, but the principles still apply to female dressing. This is for people who don’t know how to navigate the casual dress code, or who feel that they need to learn the basic rules of style. Style for the unfashionable or the uninterested, if you will.

Basically, for OSCON, as for most tech conferences and tech offices, it’s very easy to overdress and very hard to underdress. The key is to stay on the underdressed side of the spectrum so you don’t look like you’re trying too hard while avoiding the omnipresent perils of geek dress: poor fit, dated styles, and poor grooming.

THE BASIC TECHIE UNIFORM IS JEANS AND TECHIE T-SHIRTS. This is completely acceptable. It’s all in the specifics.

JEANS

• Color: Your jeans should be dark blue or dark black. Even if you are the kind of guy who lives in outdoorsy natural clothes, no light jeans are allowed. Light jeans on a man do not work.

• Detailing: Jeans should have no holes, stonewash, fading, whiskering, fancy zippering, metal, or colored or elaborate stitching. If you are attempting the elaborate stitching on the back pockets, you must be able to pull it off, and this takes attitude. If you lack the attitude, you will come across as trying too hard, which is fatal. If you are overweight and want to wear jeans, you should get dark wash on the sides and lighter on the front of the leg, since this combination has a slimming effect.

• Fit: The jeans should be as slim fit and straight legged as works for your body, and definitely not baggy. Men should never wear skinny jeans unless being in a band is their full-time job or they work in fashion. I hope I don’t need to repeat this. If you are reading this article and learning something, do not wear skinny jeans.

• Length: In jeans, as with all pants, length is crucial. They must not be too short. The ideal length is a half-inch to one inch above the floor. Absolutely no shorter. If your pants are not hitting the top of your foot and breaking so they fall longer on either side of your arch, they are too short.

OTHER PANTS

• Cargoes are also acceptable, as long as they are slim fit. If the pockets bulge out too much on the sides, don’t wear them. Carrying a ton of stuff around in your cargo pockets just because you can is a very Dad-like move. Your wallet and phone and one key are the max allowable, if you need a rule. If you are overweight at all, don’t wear cargoes because the extra fabric doesn’t help.

• Khakis: I’m on the fence about khakis. If you want to wear them, know that they give off a conservative vibe and avoid pleats religiously. Don’t get me wrong, I’ve seen guys look very good in khakis, but the vibe is always preppy, and unless you are sure that is your look and you feel comfortable in it, its better to avoid because it can make you look old-fashioned.

SHOES

Converse and Tevas are popular. Yay on the first, nay on the last.  Do yourself a favor and leave the Tevas at home. Tevas are outdoor shoes. Conferences and offices are indoors. I realize that Portland is on the West Coast and thus outdoorsy, but I repeat Tevas are for outside.

These jeans are perfect, although I would prefer them an inch or so longer. Clearly, the people at Bloomingdale’s disagree, so as you can see it is somewhat a matter of preference. But they are dark wash with no fading and slim fit. And of course do not ever tuck your t-shirt in like he is doing—that is ONLY because this is a photo taken ONLY to sell the jeans.

T-SHIRTS

You techies like your t-shirts. There is always an unspoken contest going for the coolest shirt. I won’t even begin to comment on the different ones in terms of message, because that requires knowing the ins and outs of techie-dom. The GitHub Octocat has been a favorite for a few years running now, and who’s hotter than GitHub this year, with their $100 million dollars in funding.

But for our purposes, it’s the fit and fabric that are important here. This shirt hits a few inches below the waist, is slim fitting but not too tight, and has sleeves that are just right. It is a sad truth of conference t-shirts and printed t-shirts in general, even women’s, that many of them are printed on stiff fabric and have too-high necks and too-wide sleeves. My Talk Trekkie To Me t-shirt makes me very happy when I read it but not so happy when I wear it because the neck is too high. Someone should tell RedBubble that they need to find a new shirt to use, but I don’t think it’s going to be me. Someday I am going to start a t-shirt company that uses the perfect shirt, but until then, you just have to be picky about which ones you wear. If you must collect shirts from every conference you go to, well, this is why we have clothes that we don’t wear out of the house. Note his jeans: faded and slightly baggy. He looks good though, so clearly all rules can be broken if you know what you’re doing.

If you want to dress up a bit more, put a blazer over your jeans and t-shirt. Just try to get one that is not the top of a suit. This does not work 99% of the time and it takes a sophisticated eye to know if you have hit the 1%, so buy a blazer separately. Stick with a basic one, but if you are wearing the dark jeans like you are supposed to, try to skip the plain navy blazer because then you will be blue all over. Blazers never fit correctly unless they have been tailored. I know this is a hassle, but if you want to look good and have gone to the trouble to buy a blazer, go the extra mile and get it tailored. Most department stores have a tailor on staff.

After writing this post I am wishing I worked somewhere I could wear t-shirts and jeans to work. Even if I follow all my fashion rules I still couldn’t get away with it, so if you can I envy you. As much as I like clothes, part of me wishes I could wear jeans and sneakers every day and not have to think twice about it.